In case Run-time error '13' do this...

I'd like to bypass certain steps in case type mismatch occurs.
How do I go about that?
Funny thing is once this has happened certain macros do not run again until I turn Excel off completely and restart.
Closing the workbook does not help. MS-Excel must be turned off. Is it normal? (Excel 2003)
One variable stores Error 2023 and then some comparisons in the code start to fail.
Any clues?
Thanks
Gabor

Difficult, since the code is very, very big and fuzzy, so I better explain it with words:
This is an excel-based Gantt chart.
CommandButton on the sheet offers the opportunity to the user to delete a task-line in the Gantt-chart.
So the problem occures when the user deletes a task-line where the End-date is used by another Task-line to be the Start-date. So since the Start-Date is a Formula e.g. '=G9'. So in case the row 9 is deleted some formulas that are responsible to calculate min and max dates on the chart turn to #REF! and macros that would want to use the entries of these cells will not be able to perform the required calculations.
In a nutshell this is the layout of the issue.
Actually I was buffled by the fact once the problem occured excel did not want to run some of the codes even after I have corrected the error on the sheet.
Not sure this makes the problem any more understandable.

Cheers, Gabor