Never had any problems with any features when using MPE (Ive had 3 Sony phones before) but Ive just got a new C905 and now when I send a text, the pop up ballon says "Sending Failed" occasionally, in fact, quite a lot.
The person receiving the texts usually gets them or half of them.
And to eliminate hardware things:
- use only the delivered cable which came with the C905
- don't use Front-USB or USB-Hubs. Use USB-Slot on the back side of the PC