AVR32 C++ Project debugging

Essentially we have an program written in C++ using the AVR32 platform. The program is a client application that reads 128 bytes from its RS422 port, packages them with CRC, and then passes them onto the server via TCPIP. There is also 4 other main events (triggered by touch screen for 3 of them and magetic card for 1 of them) which require data to be packaged and then send to the server. Our program basically needs debugging the data it's sending to the server isn't right we think the original programmers who did it, haven't followed the data syntax format properly. It should be fairly straight forward however, you shouldn't have to re-write the packager, just get the data sending in the right format. Upon a successful bid you'll be send across the communication spec and the current code to find out where the issue is and fix it accordingly. I've been asked approx how many lines of code, to give you an idea of scope it's probabally around 300 in [login to view URL] however most of that is for touch screen functionality among other things. The communication code is much less.