What are you trying to open it with?
If photoshop u have to installe some new plugins ans use black angels dtx converter to convert to lithtech. If you a problem reply.
do you have dtxconvert and the plugins for photoshop?, cuz that ur problem, if open dtx convert convert the file you want to edit to lithtech, open it, edit, save it as a dtx file and then unconvert it back to nexon open rezinject and inject to where ever ur gun is. good job for not leeching any more and remember to click thank