Warnings in procmail log

[Geoff Soper]

Hi,
I'm getting the following three warning in my procmail log (machine name 
removed, just in case!), I assume I'm missing some configuration 
somewhere but don't know where! Can someone advise?

Thanks,
Geoff

[8162] warn: config: cannot write to //.spamassassin/user_prefs: No such 
file or directory
[8162] warn: config: failed to create default user preference file 
//.spamassassin/user_prefs
[8162] warn: auto-whitelist: open of auto-whitelist file failed: locker: 
safe_lock: cannot create tmp lockfile 
//.spamassassin/auto-whitelist.lock.<<machine_name>>.8162 for 
//.spamassassin/auto-whitelist.lock: No such file or directory