Occasionally lp cannot find my print file. Why?

[Duane Morse]

Occasionally I try to enqueue a file for printing by

lp xxx

and lp comes back with a message saying that it cannot find "xxx". It
also cannot find it when I specify the file by ./xxx. I end up having
to cat the file and pipe it to lp. The file permissions are read/write
for everybody. Anybody have any idea what the problem might be?
-- 

Duane Morse	...!noao!{asuvax or nud}!anasaz!duane
(602) 861-7609