Problem:
You try to run a macro and receive the following error:
"Invalid Characters in CONSTANT "MERCHITEMTAB-UP". You may only use A-Z, 0-9 and _. "

Solution:
You need to find and remove all old versions of file "incUI.mac" from your computer. Delete ALL copies of "incUI.mac" that you find EXCEPT for the 1 in the ACTool Macros folder.