my gut feeling tells me that this has something to do with the fact that system() is basically fork and exec while the parent (in your case, the child :-° ) wait()s. The wait() returns with your "No child process" error.

Interlude while Robartes checks the man page for wait

Eureka. The man page for wait() states that wait returns ECHILD..

...if  the  process specified in pid does not exist or
   is not a child of the calling process.   (This  can
   happen  for  one's  own  child  if  the  action for
   SIGCHLD is set to SIG_IGN. See also the NOTES  sec-
   tion about threads.)
[download]

This is on a Linux system with glibc v2.2, so YMMV.

CU
Robartes-