Another item to add to the list of pitfalls when getting up and running with a 64bit OS…
We experienced constant BadImageFormatExceptions when running our Nunit tests via Resharper 4.5 in Visual Studio 2008, on XP64. It turned to be due to the issue described in the following post:
http://www.jetbrains.net/jira/browse/RSRP-71135
As suggested in the post, we turned off the Read-Only permissions for the JetBrains.ReSharper.TaskRunner.exe assembly and then ran the following command in a command prompt:
corflags.exe JetBrains.ReSharper.TaskRunner.exe /32BIT- /force
Problem solved (although you do then get warning messages when launching Visual Studio, which you can ignore).
According to the latest entries on the post, it looks like this might have been fixed in the latest builds.