exit code 127

Hi, i´ve set up an AutoYaST Installation Server. I want to install my clients via PXE-BOOT. When the client is booting, everything works fine but when yast ist starting, i got en error. In the log it says: starting /mounts/instsys/sbin/inst_setup yast install program exit code is 127 sync... ok i can´t find out what the hell means "exit code 127", becouse it seems that everything is well configured and works fine. thanks... thorsten