edit:
A full reinstall (Sins, Ent, Dip) solved the problem.
:edit
Hi,
I'm not sure if this belongs in the technical or in the mod section, but as this doesn't seem to be a mod-specific problem I'm trying my luck with the technical subforum.
The situation is as follows:
I'm using a couple mods (each at a time) like dolynicks sggalaxy with their respective compatible gameversion.
I can enable the mods without a problem and also play the game afterwards.
The problems start if i quit the game and load it up again with any mod still enabled.
As soon as i do that, sins does weird stuff after starting a new single player game:
1. There seems to be some kind of integer overflow resulting in the blackmarket prices being around -2.1 billion.
2. No objects are on the screen (no planet, no frigate factory, no ships) and when i zoom out i see the planets/stars but can't zoom in again. (well i can zoom in, but not close enough to see a grav well, the camera zoom stops shortly before reaching that level)
This happens in every game.
It doesn't happen if i load up sins without mods and enable them afterwards, or if i load it up with mods, then disable all of them, apply the changes and enable them again.
So my workaround is to disable all mods bevor quitting to windows and enabling them every time i start sins up again. It works but is really tiresome. 
Does anyone have an idea what causes this behaviour and how to stop it?