Motion Analysis

Problem occurs using SW 2009 Premium, Windows XP 32 bitmachine.
I have a Windows Vista 64 bit machine available but have not triedthis simulation on it yet.

The assembly I am trying to apply motion analysis to consistsbasically of a four bar linkage system that is linked to twoscissor type linkages. The assembly also contains a half sheet ofplywood for the assembly to walk/crawl across, where only gravity,friction, and 3D contact link the assembly to the plywood. Thescissor linkages are independent of each other. A single rotorymotor is added to the assembly via SW motion program, and all ofthe assembly motion is derived via that motor.
I can make the assembly move in SW Animation. I can usually makethe asembly move in SW Basic Motion however it seems if I try touse a motor and then also try to add 'gravity' problems begin tooccur, i.e. moving assembly dissappears leaving only the red arrowthat indicates rotory motor motion and also the plywood it issupposed to be moving on top of. With 'gravity' alone applied theassembly has moved as would be expected (usually).
If I try to use SW Motion Analysis I generally get the errormessage 'The initial conditions displacement failed'. It appearsthat the assembly is trying to initially instantaneously move to abeginning position that would align its' coordinate system with theplywoods' coordinate system. It has moved to that approximateposition and actually worked on one or two rare occasions.Generally the model explodes into positions physically unattainableand/or pieces physically disconnect from each other. At this pointit is difficult and sometimes impossible to get the model torebuild to its normal configuration.
Note that the assembly contains zero reduntant constraints, I havetried increasing the initial integration step, decreasing minimumintegration step, maximum integration step, and also tried allthree solvers (and probably a hundred other nuances to the model orsystem parameters).

Any help would be appreciated.

Regards,
John Ashton

SolidworksMotion Studies