Yaron,
Can you please clarify: You said "If I remove the STS_set/STS_delta commands from my code "go main" is performed without a problem".
Do you mean that if you remove the calls to these functions in your code then you can get to main()? Or are you saying that if you remove the STS object in your configuration then you code gets to main()? Since these code is in a Task...I would think removing the code has no bearing on getting to main().
Most likely either you ran out of stack space or maybe heap space. I tried adding an STS object to a simple example and got to main() without an issue.
Judah