Error: "Cannot create semaphore ..."?

Hi, has anyone seen this error message before?

Cannot create semaphore /tmp/qtembedded-0/QtEmbedded-0 'd'
Error 22 Invalid argument
Cannot get display lock

I googled the error but still have no idea what it means. I couldn't find anything in the Qt source files that contains "Error 22 Invalid argument" either.

I'm using QtEmbedded 4.5.3.
Thanks in advance.

what are the access permissions for /tmp/qtembedded-0/ ?
Does your user have write permission there?

the directory has permission 700

root@(none):/tmp# ls -l
drwx------ 3 root root 80 Jan 1 08:04 qtembedded-0

I'm running under root superuser. If I tried to change the permission to 777 or 755, it will say "Qt for Embedded Linux data directory has incorrect permissions: /tmp/qtembedded-0"

Thanks

Well, I just reboot the box and it runs fine again. Permission of /tmp/qtembedded-0 stays 700. But I still don't understand how that seemed to fix the problem?