I have the same issue. I have tried everything and I mean everything mentioned here in these forums.
It is definatley a cookie issue.
I eventually got my blog going by deleting everything, installing 1.2.2 Mingus, setting eveything up and then upgrading to 1.5 beta and then it worked. I presume if you do the same with 1.5 Strahorn it will work too.
Only problem is now I can only login on the one machine which is a pain and I cannot change my password.
What is the difference between your 2 hosts?
Good luck!
