=IF(ISERROR(A1),"There is an error in A1.",A1)
Is a circular reference, and quite possibly will result in the end of the universe.
However, you could do something like:
=IF(ISERROR(A1),"There is an error in A1.",2*A2)
where 2*A2 could be any valid formula or function.
If you want A1 to APPEAR to be blank if the formula results in an error, you could use:
=IF(ISERROR(A1),"",2*A2)
However, having stated all of that, I'm not sure if #VALUE is considered an error. There is ISNA(). I forget if there is ISVALUE().