Looks like the first message used the American journalism standard of putting the end-of-sentence period inside the quotes. That's a bad thing to do when feeding error information to users. The second message does not have the period, so that's not the issue.
It is complaining that the value of "false" is being passed to something called "RTI Client Tracker". Presumably, in the background you are passing information to RTI's software. My guess would be that there is code, somewhere, that is calling an RTI function or procedure, and that has an expression in the call that is being evaluated to the value of "false".
I notice that you have a document called "RTIClientTracker-Betsy" that is being called from DataSheet_Click().
Try this - make a play copy of your database and comment out the following two lines.
Code:
stDocName = "RTIClientTracker-Betsy"
DoCmd.OpenForm stDocName, , , stLinkCriteria
See if the error persists or changes.