The concept of xmodem is to ensure the file arrives correctly.
http://code.google.com/p/arduino-xmodem/
Simple xmodem implementation for Arduino
So, you are mixing xmodem commands and regular print stuff on the same serial port.
No wonder the receiver gets confused.
Is the receiving application communicating over the serial port correctly? Is it running the right code? What happens if you quit mixing data on the serial port?