I have installed a version of Sitecore Intranet Portal for one of our customers. We now have the problem that the stylesheet can't be loaded. After a while we get a 504 error. In Firefox everything is working fine as this will just load the old stylesheet that loaded before. The new stylesheet won't be loaded and just gives a gateway error. Could this be server side caching or whatever? If so, how can we test / solve this problem. The website is running on a Windows 2003 R2 server with 3gb ram. When i'm renaming the stylesheet i am able to load the stylesheet, but when i rename it back to it's old name it refuses to load and gives back the 504 error.
The name of the css file is: