Alright, I'm pulling my hair out here...
Here is a page I'm having a problem with: http://www.fmgrinding.com/blank.html
See the spaces between the images in the navigation bar?
Now, here's a page without those spaces: http://www.fmgrinding.com/blank2.html
The ONLY difference that I can find between these two pages is the fact that the source code first (blank.html) is formatted for readability (indented, etc.) and in the second one, the source code for the navigation bar section is all run together. I've tried fixing this through CSS, etc. It seems that the only option I have is to remove all that whitespace, making the code impossibly difficult to read.
Why is this? I thought whitespace didn't bother HTML! This problem replicates across various browsers. Can anyone tell me what's happening here?