Problems using Xmodem

Hello,

Iam facing a problem, i hope that some can give me a hand in that.
I was able to install Qnx on my IPAQ 3870. I was doing file transfer
using xmodem via serial port and suddenly it crashed and i was not
able to do any transfer anymore. I tried another protocols and even
i changed the PC that connects to the IPAQ , nevertheless i was not
lucky.

Anyhint Please ???

Thanks in advance

Bassel