I had a very spooky issue today that took me a good deal of time to resolve.
On a list in an English variation I have a calculated column called CalculatedExpiry with a formula that looks like this:
and that works just fine, if the Expires field is empty, it set it to 1. January 2099
I then created the same calculated column on a Danish variation of the site, but when I wanted to save it I got the "The formula contains a syntax error or is not supported."
Even though they where identical...
After a lot of testing and googling I came accross this post, which suggested to replace the commas (,) in the formula with semicolons (;) and what do you know, it works!
So in the Danish variation the calculated columns formula now looks like this: