Can anyone figure out what is wrong?

[codedr]

It looks like your program or some other function (perhaps on your behalf) is calling strstr() to find a substring in a larger string. Are your processing strings in your code?

If you are, I would guess that some assumption you've made about the string always having that value is not true, or your code is not finding the ending condition and is continuing past the end of the string searching for the value.

Are you able to get a full traceback of the stack when the failure occurs?

I would try and find out what the last thing you are doing in your code before it crashes.
Using printf() or logging to narrow the location down might help.