Long filename error

Scandisk for DOS, when started automatically on booting, reports a long
filename error on the system partition and tells me to run Scandisk in
Windows. The latter tells me no errors found.

I wouldn't mind, but Scandisk stops at the error and waits for a key to
be pressed. This means I can't go and make coffee and come back with
booting finished and the restart after a power outage won't work.

Scandisk does not tell me which file is wrong and looking over a DIR
listing nothing struck the eye - of course it's far to long to read line
by line. I'm prety sure I can repair the problem manually, but I first
need to find the culprit file. Any ideas how to do that?

Danke
Axel