Oh yikes sorry to zombie an old thread again, but yeah my mileage claim got rejected due to:

"Retroactive mileage claims for your Jetblue Airways flights were rejected due to ticketed name not found. For us to assist you further, please email us a copy of your Jetblue Airways electronic ticket or boarding pass for review..."

I was basically hitting the 6 month window at this point and was too lazy to fight this, so I ended up just crediting to Jetblue (which happened almost instantaneously on their website). Maybe my names didn't match (sometimes my middle name gets attached to flights/accounts and that frequently gets messy given that it's more than one name)?

Sounds like the fix to this is to get the gate agent to add your KrisFlyer number to try to avoid the online process.