A rescan is strange, I have not had to do that, which version of the Windows client are you using?
I remember that just before the Dev that released this coin vanished, he released "patched" version which was supposed to help with the crashing issue.
That is the Windows client that I have available to download at Zirkcoin.org at the moment.
With so many projects going on at the moment, I really do not see how I am going to have enough spare time to support this Crypto at the development level.
I will try and at least develop and release a much more simple and bare bones client, that does the same job as the current one, just without the bling which could be causing the errors.