2013r1 Assertion failed

I have a SOAPMethod invoke inside a loop, after a few records i got the error below:

Assertion failed: (!!(srcCharLen > 0)), function sendOut, file /Users/realsoftware/BuildSlave/QuickXCode/build/REAL Software Plugins/Xml Plugin/Sablot-1.0.1/src/engine/output.cpp, line 995.
Abort trap: 6

You should create a Feedback case with an example project so we can look into it.