Th article suggests a text area can be an arbitrary length, however I have experienced failures to enter data when the entry is very long (somewhere around 1900 characters seems to be the limit) the edit fails and the page is left completely blank. Is this a variable that can be adjusted somewhere?
This sounds like an issue with Semantic Forms, not Semantic MediaWiki. But the issue might be a setting you can change in PHP or Apache (assuming you're using Apache).
Yes, I am using Apache. Have you any idea where I might look to diagnose what the problem might be?
I don't know, sorry. It should be something related to submitting text from within forms, using POST.