Unable to run qmail-remote??

[Ralf Guenthner]

Hi

I had some undeliverable messages this morning and the reason stated by qmail was 

Unable to run qmail-remote. 

What could be the reason? System is qmail 1.03, running supervised as suggested in the 
FAQ: supervise /var/run/qmail /var/qmail/rc

Thanks for any hints
Ralf