I resolved the problem with SSI (see the other thread), but I continue to have a 500 Server Error whenever I try to save the Contact page. On a test website, it doesn’t happen (same page contents, same templates).
I also tried to delete the index.shtml file, then the “/contact” directory itself, in a hypothesis it was a permissions problem, but without results.
Any idea?
Reported on Movable Type 4.2

And you are using fresh templates, no SSIs or PHP, etc.?
The problem happens in both cases: it happened when I still had the fresh template, and now that I have a SSI statement in Footer Links.
I didn't try to other pages. Anyway, when I saved the About page, I didn't have problems. Only on this one.
The strange thing is that if e.g. I put "hello world" in said Contact page, it saves w/out problems. If I had some html (very randomly, I've seen), it gives error. But on the other hand, the same html code doesn't give error on the test website.
Weird. Have you tried recreating the HTML that errors out using just the rich text editor?
Mh, not. It's a lot of links, Mike :)
Well, you can recreate parts of it...
Yes, but it already works, this, but then it doesn't work again. It's the "randomicity" of the issue that's makes me mad.
I give you an example, to explain:
at the first, i rewrote the page as you said, in a step-by-step approach.
I wrote some links: Saved. Ok.
I wrote other links: Ok.
I wrote one more link. Error.
I cut this link: Error.
I add other links: Ok.
I arrive on the bottom of my page: Ok.
I go to make a little modify on the SAME page: Error.
I revert to previous page: Error.
And so on...
:-(
Actually I put the Contact page via ftp... it's not the solution, because when I'll update or rebuild it will overwrite the page.