Can you give us the specific wording of the error?  It falls beneath the line that says "The Firebird database engine has encountered an error..." It should give a literal, albeit technical, answer to your question. 

We can clarify the situation based on that, and the specific version/build of Timeslips you are using could be of benefit as well.

Can you give us the specific wording of the error?  It falls beneath the line that says "The Firebird database engine has encountered an error..." It should give a literal, albeit technical, answer to your question. 

We can clarify the situation based on that, and the specific version/build of Timeslips you are using could be of benefit as well.