Any one know what make this happen when I import a obj file nothing happens and the menu options is blacked outh so I can't do any thing but close poser down ??? Oh it's p4 on a win-xp pc.

Try loading the OBJ file into UVmapper, then saving another copy, and loading that into Poser.
This may fix whatever problem exists in the OBJ file, otherwise you'll need to load it into a modelling program and see if that spits out an error message that's helpful.

I have tryed both things but it dont help so I tryed to import one of p4 obj files it do this even when I try to import one of p4's own obj files...!

I dont know if the import/export pugin can get croupted ..?

It could be a problem with that component, yes. Poser seems to have a talent for corrupting things sometimes. You could reinstall Poser over the top of your existing installation, or if you don't want to risk that, make a new installation somewhere else; then copy your runtime across once you're happy it works.

hmm..not that it should matter, but I've had problems if the accompanying .mtl file isn't included..but that's me..;) that's mainly for self-created ones, tho..