If you're doing what I thing you're doing, try this syntax:

Me.Controls("tot" & pParam)

Sounds like you've used naming conventions for controls using
numbers.

Your mistake is in using the wrong method for concatenating the
name. What you want is:

 Me("tot" & pParam)

You'd use the & concatenation operator because you don't want to
propagate Nulls (the + concatenation operator propagates Nulls, so
that if pParam is Null (assuming it's a Variant and can be Null),
then you'd be passing Me(Null) which will generate an error.
Me("tot") will also generate an error if there's no control of that
name, but probably a less serious error).

I'm not at all sure what this has to do with arrays, though.

Also, It sounds like you're populating repeating data, which sounds
like a possible design error somewhere along the way. Now, I've done
exactly what you're describing in particular situations, but it's
something of a kludge, in my opinion, as it ties your code to
objects on a form having been named in a particular fashion.