Convergence issues on Vista vs Windows Server 2003

[grahamo]

I have created an optimization algorithm to run with OpenSees. I ran it successfully on an Windows Server 2003. While running it there I have not had trouble with convergence. However, when I run it on my Vista laptop, I repeatedly get the following error.

WARNING: CTestEnergyIncr::test() - failed to converge
after: 10 iterations
NewtnRaphson::solveCurrentStep() -the ConvergenceTest object failed in test()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 12.48
OpenSees > analyze failed, returned: -3 error flag

I thought that this was an interesting occurence. Is there any known reason as to why this would change between the two systems? Thanks.