I updated an install of 1.2 I had for testing purposes with the 1.5 files from the download page.
A ran through all the upgrade stuff without problems, but when i try to login, a successful login just redirects me back to the login page. (As oppossed to an unsussesful one which goes back to the login page with an error)
I also tried a fresh install, with a fresh database, but get the same problem.
This is a windows 2k server. Tried using both FireFox and IE, tried deleting cookies, made sure they were enabled etc...
No modified files except wp-config - even tried letting wp create one itself...