If you want to make address directly, the worksheet must exist.
Turning off automatic recalculation want help you :)
But... you can get value indirectly...
.FormulaR1C1 = "=INDIRECT(ADDRESS(2,7,1,0,""" & strProjectName & """),FALSE)"
At the time formula is inserted it will return #REF error, because strProjectName sheet does not exist.
But after this worksheet appear Excel will calculate formula again and proper value will be shown.
Disadvantage: there will be no tracking, so if you move the cell or change worksheet name, the formula will not adjust to the changes as in the direct addressing.