You won't get an error there with the exact code you are showing - it won't do anything, but you won't get an error either.
You almost certainly will get an error if you try to set the ForeColor property of
label
though, as the MSDN page says very explicitly:
In order to receive a valid value from this property, the object that calls it must either contain or be contained in the control it is calling. If one form tries to call another form's ActiveControl properties, it will receive an undefined value. In this case, you need to define your own communication mechanism between the forms to pass this data.
Since that is definitely not the case here, you will get some odd errors occuring...
Don't do things like that: it's not exactly difficult to do it properly.
See here:
Transferring information between two forms, Part 1: Parent to Child[
^] and implement the "Property method"