Omeka has encountered an error. I can't see the collections

The collection show is not seen. Error Notification:

"Omeka has encountered an error
To learn how to see more detailed information about this error, see the Omeka Codex page on retrieving error messages."

What can I do to see de collections?

If you follow these directions to turn on error logging, you should be able to retrieve a specific error message:

http://omeka.org/codex/Retrieving_Error_Messages

This will make it easier to troubleshoot your problem.