Most if not all the old IKM 32bit only software require the host to run as administrator. Try running SONAR as administrator.

Had the same problem. Miroslav is just Sample Tank 2 with dedicated skin and orchestra samples. You may download free ST2 from IK site (this time it should be seen as a new Sonar plugin) and then in prefs point to the folder where you keep Miroslav samples.  You will have fully functional Miroslav but with basic ST2 skin.

The easiest thing to do , albeit more money, is to purchase Sample Tank 3 ST(it was on sale recently for 49 dollars) and import MP and any other 32 bit IK library into it.
 
I have Philharmonic, Sonik Synth, SampleMoog, Sampletron, and dozens of IK grooves  and LKibraires that I fought with under Jbridge .
Crashes, white and blues screens, etc...
 
Since purchasing ST3 SE and importing, no more problems... On one hand they are all OLDER libraries and much better is out, but I had all that invested, plus Philharmonic is a darn good ork library for the money.