Mipmaps in Gimp dds-Plugin

Hi together!
I need some help again.
Since I have a new PC, I hadn't have gimp installed, till I wanted to do a new skin. It's finished and works, but only when I am driving it. I get a game crash, when the AI tries to drive it...
I think it could be because of the wrong amount of mipmaps, I used another program for this, but since I have the dds-Plugin for gimp, I am not able to decide the amount of mipmaps to create.
Can somebody tell me, how I am able to fix the number of mipmaps in the Gimp dds-plugin?

I've always used DDS Converter 2 for skins done in Gimp and used 5 mipmaps. I think Gimp defaults at 11?
I didn't realise too many mipmaps could cause a ctd when the ai use a car, i just thought a high number would slow the game down?

I don't really know, but it is the only explanation i've got for this...
I also used DDS Converter before, but on my new computer it didn't work, so I tried the dds-plugin...