Disk Utility Error "Storage system verify or repair failed"
The error is not caused by enabling FileVault 2. 

Context: 


FileVault 2 uses Core Storage
to verify a logical volume that is in coreStorage world, Disk Utility will run both fsck_cs and more traditional fsck_hfs.



  fsck_cs does not perform an exhaustive validation, nor is it able to fix many
  of the inconsistencies that it does detect.


That said, I should not be immediately worried about the class of error given in your question.