I recently bought a new PC and have been installing a bright sparkly new set of 64bit applications and marvelling at the speed of them and highlighting the lack of speed of my brain at the same time.

I was just going through the process of checking out our rails apps and getting them up and running when I hit on issues with rails connecting to 64bit mysql using the mysql gem.

The error it showed was:

193: %1 is not a valid Win32 application

After trying a lot of different solutions, this one finally worked. Wonderful and simple, courtesy of stackoverflow.com and osdir.com

Simply copy this libmysql.dll file into your ruby/bin directory and hey presto!