Working named ranges in multiple sheets from vba

In the following:

Set I_Pts_2_Range = Range(Range("I_WP_2b").Offset(1, -1).Address & ":" & Range("I_WP_2e").Offset(-1, -1).Address)

'Inventory Assessment page ranges
Set IA_MC1_r = Range(Range("IA_MC1_b").Offset(1, -1).Address & ":" & Range("IA_MC1_e").Offset(-1, -1).Address)

Both I_Pts_2_Range and IA_MC1_r are defined as ranges

Dim IA_MC1_r  as range, dim IA_MC1_r  as range

The sub they are in is initiated while on the sheet that has the ranges' addresses that follow in the first line. All the ranges and addresses that follow in the second line are on another sheet ("MC Inventory Assessment"). Each of the named ranges on the right side of the assignment are single cells.

The first line of code runs fine, doing what it is supposed to do, but the second line blows up in an "application-defined or object-defined error". I don't get it, for I thought that the names were supposed to be work-book wide in scope. If one implementation doesn't work, then why not the other?

Can anyone tell me what I am doing wrong and how to make it work?