> I'm willing to delete the files, as they are
> usually ads, but don't know how to do a search for long
> filenames, and the file names are too long to copy by 
hand.

A bit offtopic :)

Unix/Linux or Windows with cygwin tools: just use the find 
command in a bash window:
find . -type f | grep -vE '.{100,}' | xargs rm -f

Windows: a bit harder:
Start/Search/Search files in the desired folder
Launch the find process to list all files.
Then, using the mouse, create a selection frame as if you 
wanted to select several files ; by dragging the mouse from 
the upper right corner to the upper left corner - but not 
the full left side - leave a space which will prevent you 
from selecting files with "small names". Then drag the 
mouse down - this will select all "long file names".
A bit experimental and not vert precise as you'll have to 
take in account path names ; but I don't know a better 
solution.