OWE ticket with Non-OW flights
 

Any problems/potential problems along the way, with OWE ticket that contains Non OW flights?
My travel agent says she does it with Star-alliance RTW (mileage-based), but she has no experience with OWE.

Not sure I fully understand what's going on with this, but if you're using a Oneworld Explorer (and, I think, Global Explorer) RTW ticket, you are limited to the Oneworld carriers, codeshares where both the operated and selling carrier are Oneworld members or select other carriers that operate as regional affiliates or franchise carriers for a Oneworld member. You cannot on a OWE fly United from Chicago to Hong Kong, for example.

Perhaps your TA is talking about another RTW which might mix and match carriers from different alliances. But, if it is a Oneworld RTW product, your travel will be limited to the Oneworld carriers.

Sorry, my initial post was NOT clear.
I'm talking about a RTW OWE ticket that has non OW flights PAID EXTRA beyond the OWE itinirary price.
Any problems on having on SAME ticket the OWE flights and some Other flights?

The non-OW flights won't be on the same paper ticket but there is absolutely nothing to stop you from buying the extra segments - carrying two paper tickets I am sure won't be too taxing.