The reason mine started as paper tickets is that, at the time, SQ could not interline e-tickets with LH or UA.

I see... The reason I asked because according to SQ, maximum number of segments (including any open jaw) in the E-tix is 16 only.
Actually, it is intereting to know that your paper tix were changed to E-tix later on. I had one rerouting with 10 segments left on UA and SQ, but it was still issued as paper tix... because the original routing was 20 segments at least.

Mine were reissued by UA after all the SQ segments had been flown, so they became LH/UA e-tickets. SQ/UA e-tickets only became possible in the last month or two.

By the time mine were reissued, I'm sure there were fewer than 16 segments remaining. Both or all of mine were orginally issued in CAI by LH or SQ.

Update
 

I missed my BKK-XSIN-LHR flights. I was rerouted to BKK-XSIN-XZRH-XFRA-LHR. Again, the E-tix was able to be issued on LH, UA, SQ only. ZRH-FRA there was an earlier flight on LH codeshare with LX. But if I took that flight, the paper tix would be issued. Also, I was offered to take BKK-LHR on TG (which I declined), which requires paper tix to be issued.

TG seems to be offering e-tix on some routes, mostly from BKK. Check out the timetable on the TG site. So an etix RTW could include TG.

It is true that TG offers E-tix. But that's for their own routes. In RTW E-tix it's related to the compatibility of the E-tix among the airlines. For example, between UA and TG, UA can not issue an E-tix if the itinerary SFO-NRT-SIN-CGK includes TG flight, but it's an E-tix if using SQ for SIN-CGK.
Yes I did E-tix on TG domestics, but it was not involving any other airlines.

This spring, UA issued an F award e-tix for MUC-FRA-BKK-HKG-BKK-FRA-MUC, operated by LH and TG with LH and TG flight numbers. 6 weeks earlier, they weren't able do this for the same itinerary, so it's a new feature.

I'll like to pitch in my two cents here. My current RTW (stuck at SFO due to ticket-hell) was issued as an e-tix and given the choice I would not do this again. SAS has made a full and utter hash of this from end to end.

During checkin for segment 1, a SK segment they couldnt even find their own ticket, given the registered FOID. At the second segment (LH, handled by SK), they claim my FOID wasnt registered, and demanded to se my EB-card, which showed a handfull og segments here and there, but nothing connecting.

After this I went to their ticketing desk to demand a paper ticket, as I could see this forbode hours of problems down the route. Halfway through printing the ticket the woman behind the desk claims "oops, can't print UAX-segments, take what I've printed, the rest works as an e-tix".

Since I've had hell, SK claims everything is in order, UA won't check me in, and claims there is no valid ticket, either by FOID, their own recrod locator or by the document number used to issue the ticket. The only reason I got to fly JFK-SFO today was that my TA issued a seperate ticket for that leg. UA still claims I have no valid ticket for my next segments, and SK tried to calm me by saying there is no problem, I mus tonly try to tell the UA staff that they must be wrong.

As far as SK is concered in my future, I royally hope they collectively get run off a cliff....

And to update the world on my etix RTW hell: got a mail this morning, my TA says SK says theyve spoken to UA and that I was more or less imagining my problems, and I should have no problems at on EUG-PDX today. Well... after half an hour of agents phoning and talking they ended up concluding they had a sort of valid ticket, but there is on payment for the UA/UA segments. Right.

For the third of five segments no my TA has shelled out a seperate ticket and need to go sort issues with SK, and we already know there will be more issues in PD tomorrow morning.

Regarding the problem you encountered, perhaps SK and UA E-tix are not talking to each other yet.
My SQ, LH, and UA RTW-tix was working wonderfully so far (issued on SQ stock). Took LH LHR-MUC-SFO connect to UA SFO-YVR, all the BPs were issued properly, and the E-tix number were printed correctly on the BP. And yes, in united.com "My Itineraries", I can see all my reservations for UA flights, as well as the E-tix receipts.

SK-UA e-tix interlining should work. it's just something cursed about this ticket. I spoke again to UA ticketing in PDX and they told me it now seems more or less valid, except payment is now gone for all the segments.

So far my TA has had to issue seperate tickets for JFK-SFO-EUG-PDX on their own dime to get me along my itn, and resolve issues behind the scenes with SK.

(It's issued on SK/117 stock.)

-A

And after being fed up with another reply from SK that all should be fine I did some digging, and found the root of this hell.

My RTW is issued on five different, consecutive, document IDs. When SK in OSL decided reissue was the safe way to avoid e-ticket internlining issues it went down the drain. What happened was that that person did a reissue of the part of the first and second document ID, and the segments that person was unable to print was quietly discarded. Result, a patchy ticket containing a few segments, but none of the ones I had issues with. Only after I myself on the fourth day now dug through SKs billing dept. did we wint and link up the various bits and document IDs and found that segments had gone missing. How both United and SK have been able to claim over a number of days that all looks rosey is beyond me.

Hopefully my agent will be able to resolve this in four hours, untill I'm at the airport, and now, bed.

Guess what? I've left the hotell, been at the airport and I'm no rechecked into the same bed... UA blames SK and SK blames UA. But I'm not going anywhere, so says UA. SK says everything is fine and tells me to talk to UA. UA says get bent and talk to SK. The next person that recommend me and e-tix for *anything* will have intimate acts performed on him/her with a e-tix receipt. And now, back to bed, still left in PDX.

Wow, sorry to hear this. :( Hope you have nice weather in PDX.

6 miles visibility, 4C temperature, pissing down rain, westerly brisk winds.