This is just a stab in the dark, so I will keep it brief:

• Existing VFP app that includes the Client Tools / Utils, version 5.70.
• Same version running on multiple configurations at different clients: under Windows (only), Windows workstation accessing file server, ThinStuff XP/VS, Citrix and Windows 2012 Remote Desktop Services.
• Client moved from local Windows server + local workstation configuration to Amazon cloud server using RDS.
• After the move, the app showed the error "Variable 'OCT' not found" early in the start (prior to main form appearing). Selecting "Ignore" allowed app to continue without any further problem.
• The error now reads "Variable 'NOV' not found". It is now November. Big clue, but WTF?
• The client is in France, but the error never occurred until now.
• I cannot dupe the error in the development environment nor my Win 10 test system, but was able to set some existing flags on the AWS production server to trace the error to what appears to be the application's .Show and its launch of the main form.
• I'm posting here only because doing a search on "MONTH(" produced only a handful of instances, five of which were in wwutils.prg.

Has anyone seen odd behavior like this? The only apparent change is moving from a (Paris) server to the (European) Amazon Server 2012. Thanks for any advice or input.

That sounds like an EVAL() or Macro error - something is executing code dynamically and getting an unexpected value.

My guess is, it's a language thing - server may be running in a different language and the values are not correct.

Without more info this isn't really going to be trackable. You need to log errors to find where the code is breaking...

+++ Rick ---