Forcing a 404 error when file not found

I know this seems to be foolish, but the drupal integration module or the Gallery2 itselfs seemns not to have a simple 404 implementation. (I'm using newest Gallery2 and Drupal 6.x module)
My case :
One user had a large user-album on my site, and he linked his photos all over the web. Now he's gone, and he had taken his gallery with him... and I'm stuck with all the errors.

It would be great if the gallery could print out a simple 404 error instead of :

Error in function '_gallery_init()' (gallery_base.inc:144):
Unable to initialize embedded Gallery. You need to configure your embedded Gallery.
Error (ERROR_MISSING_OBJECT) : Parent 13 path That_Users_album
and so on...

Is there any way to deal with it ? Maybe get a global 301 on /v/user/That_Users_album/*
There were looots of files in that album so mapping them one by one is a load of work.