Error message re killing non-numeric process: help please

[Alastair]

I have been running --pvr as cron job every 24 hours at night.
I woke up to find machine stalled with a stack of get_iplayer processes running but nothing 
happening.  Couldn't find how to stop them other than killing them and now when I try and 
start --pvr in console I get error message:

Can't kill a non-numeric process ID at /urs/bin/get_iplayer line 2820.

Please could somebody help me sort this out.

Regards,
Budgie