Thread:Extension talk:Scribunto/Cannot create Module page

I installed Extension:Scribunto for my wiki. But I cannot create new Module pages. After I created a new Module page and click save, for example "Module:Bananas", it shows the following message:
 * [35c6e447] 2014-04-11 07:25:09: Fatal exception of type MWException

Anyone could kindly help me? Thanks in advance!