It looks as if a crash happened in the apache child process.
Take a look at the apache error_log.
If you find anything wrong please contact me through support at nusphere. You will have to provide the following info
1) version of apache
2) version of php
3) binaries packager (who has provided apache and php) or if you have compiled them your self
4) full list of options used for compiling apache and php

I submitted a support request via the nusphere email support form with the full list of details you requested and some additional findings.

I found that the httpd child does not segfault and continues to work after the debug session ends. The problem seems like a connection timeout which I can't find a reason for.

run phpinfo and make sure that dbg.so is 2.14.9