Reality Factory

I am getting the above message when I try to compile a level, followed by 'GetLastError returned 126'.

What does this mean, and more importantly what do I do about it.

Have searched forums and am not having any joy. Appreciate any help.

Have you tried the tutorials?
http://www.realityfactory.info/cms/inde ... /tutorials

You should try them and post here if you still experience the same troubles.
In my opinion the most likely case is that your level isn't "sealed" properly. To test if it's the case, try to build a big hollow cube around your level geometry and try to compile again.

Are you sure you installed RF properly? I mean the full install? gbsp.dll errors don't happen very often and 'Unable to load gbsp.dll' sounds like it can't find the file.