I finally got a section of my code to run in parallel with OpenMP without errors. When I deployed the dll to another machine, however, it no longer ran in parallel.
Logging reveals that omp_in_parallel() == 0 on the other machine but not on mine.
My machine is using an Intel i5 CPU which has 2 hyperthreaded cores for an effective omp_get_numProcs() == 4. The other is a virtual machine with 2 processors assigned to it on Microsoft Server 2008, thus omp_get_numProcs() == 2.
Are there known settings which would make a program run in parallel under certain values and not others?