I apologize but I have no answer. Only questions.
What program was used to create the OMF?
Have you had problems running normal project files in S Pro?
Have you opened OMF files in the past without problems?
When opening an OMF SONAR pops up a nag screen for Title, bit depth, sample rate etc... Have you gotten to that screen or does SONAR close before that?
Again apologies, but I have not had problems opening OMF's. Maybe the OMF was embedded with AIF audio files (or whatever the apple extension is, I forget) instead of WAV. ?
Anyway, Buying PT is a personal choice. But it does seem to be an expensive method for opening projects in SONAR. The whole point of OMF is cross-platform compatibility.