We are currently running a PhenoTips server with 955 patient records, and we plan to add many more. However, PhenoTips now refuses to import backup copies of the wiki. To reproduce:
Click Administration, Export, Export.
On another PhenoTips server, click Administration, Import, browse for the file, click it, and click Import.
The GUI says "Failed to import documents. Reason: Server Error" and the console says "java.lang.IllegalStateException: Form too many keys".
This appears to be the same bug as http://jira.xwiki.org/browse/XWIKI-11597