Thanks for asking the questions. I went back to the user and got a different story:
These two problems existed ONLY when copying files to EXTERNAL drives. There are 3 externals, all formatted for Mac Extended Journaled.
This convinced me to zap the PRAM again and the problem cleared.
My...
G5 iMac, 10.5.7
File Name Too Long and -50 errors when attempting to copy files on the boot drive OR to external drives. Boot drive has plenty of free space. Files have short names with no questionable characters in their file names.
Booted with the Leopard Install disc and repaired minor...