I removed all records from the table and now the error is gone however in Firefox I still can not double click on events in Month view to open them in edit mode. In IE this works perfectly fine.
Original problem was caused by invalid rec_type value, not quite sure how it can appear in db.
As for second problem, which version of FF you are using? There is known issue with FF9, which caused similar issue ( FF10 works correctly )
Yes I found that Firefox 10 works correctly. I also discovered dragging a reoccuring event in FireFox 9 causes the reoccur event for that day to be deleted. This does not happen in FF 10.
The problem however is if someone uses Firefox 9 unknowingly they end up deleting things unintentionaly. Is there anyway to defeat the deletion in FF 9 by adding code in the connector script.