Cannot open some .DDS files

[Anakarsis]

My .DDS converter cannot open some .DDS files of the XGM, for example the skin of the Berserkers or the imitatio legionaries. I get a CTD in the COnverter, and when i try to convert them with another program, Alpha channel goes weird and black backgrounds appears in the unit skins....what i´m doing wrong?

[Zarax]

You're probably trying to open models from the alex expansion, they cannot be edited like the normal ones.
You can ask Redfox for advice.