Problem with paint.net and moding DTX files

when i try to edit the DTX files in Paint.net it comes up with this:

The image Type is not recognized, and cannot be opened.

Please help me i realy want to mod

Did you convert it?

with the dtx converter to lith Tect yeah

just read the manual again thoroughly and you might find you have missed a step otherwise it might be because of your firewall blocking something !