-uncook is a helper for -export, but this option will not force umodel to start exporting. You should add -export option too.
Oops, sorry for the Newb question
What error you've got with these files in 3ds Max? Did you updated ActorX Importer script? (it should be 1.24 in order to load recent PSK/PSKX versions)
I will have to check for the error, I'm not able to run max until I get home.
mesh SFXPawn_Ravager.RPR_SCR_NKDa_MDL has 24232, what means 72696 indices - such mesh cannot be exported as PSK (too much triangles), that's why it is saved in PSKX format.
I see. Interesting. But I get the same 'error' when exporting from L7_Shock_Base_m package from Transformers DOTM with new UE Viewer, but when I export from old UE viewer it works with no errors, and can import to max:
Exported from New UE Viewer (viewed in Deep Exploration):
Exported from old Old umodel (viewed in Deep exploration):
Here is the package for reference:
http://www.mediafire.com/?p44qbrk8wq9v4wr