Ending Looping Macro

I've got this code that is giving me an error (Run time Error '91').

The code is looking for formulas that begin with "=XXX" and copy/paste values any cell that contains this formula.

Here is the code:
Sub XXX()
Cells.Find(What:="=XXX", After:=ActiveCell, LookIn:=xlFormulas, LookAt _
:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:= _
False, SearchFormat:=False).Activate
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
End Sub

Sub XXX_Loop()
Do
XXX
Loop
End Sub

You can probably tell that when Excel doesn't find any additional "=XXX" formulas, the error message pops up. I've tried a few things and nothing seems to work.

Although the macro is doing what it needs to do, I'd like to have a "cleaner" running macro that doesn't end with an error message. Any help will be greatly appreciated.

EDIT: The simple solution would be to copy/paste values the whole worksheet but I would like to leave some "live" formulas (e.g. "=A24/A25") that do not start with the "=XXX" custom function.

Thanks,
cparaske