A timeout error.

I have a select input that is calling a cfc via ajax. It works great,
until I leave it for a while a coffee break or lunch. I get the
message below returned. Is there somewhere or something that I should
check/change first?

Error invoking CFC /docLib/model/docLibrary.cfc : Error including
model mappings file: Could not find the included template /docLib/
model/config/modelMappings.cfm. [Enable debugging by adding 'cfdebug'
to your URL parameters to see more information]

Thank you for your help.

Is the cfc you are calling the coldbox proxy? This is worth reading: