Batch upload adding underscores to filenames.

[louis.b]

Batch upload is adding underscores to filenames.  My files are all named in sequential order...

P1020325.jpg
P1020326.jpg
P1020327.jpg
P1020328.jpg

I u/l them via ftp then when I login to batch add them, Coppermine renames them like...

P1020_25.jpg
P1__0326.jpg
P10203__.jpg
P102032_.jpg

I'm on 1.4.6 and the filenames were fine...for a while.  But during the addition of my 5th (approx) album the filenames started getting messed up!?!?    This is being run on a Windows server, with PHP 4.3.1, GD2.

Please help.