Hm Which versions of threads and Win32::OLE do you have? I get this, but no trap:

c:\test>perl
use threads;
use Win32::OLE;
use Win32::OLE::Const 'Microsoft Excel';
No type library matching "Microsoft Excel" found at - line 3
Win32::OLE(0.1702): GetOleTypeLibObject() Not a Win32::OLE::TypeLib ob
+ject at 
c:/Perl/site/lib/Win32/OLE/Const.pm line 45.
^Z
[download]

Theoretically, use Win32::OLE::Const 'Microsoft Excel'; is roughly equivalent to

require Win32::OLE::Const;
Win32::OLE::Const->import( 'Microsoft Excel' );
^Z
No type library matching "Microsoft Excel" found at - line 2
Win32::OLE(0.1702): GetOleTypeLibObject() Not a Win32::OLE::TypeLib ob
+ject at 
c:/Perl/site/lib/Win32/OLE/Const.pm line 45.
[download]

And it certainly elicits the same response. Maybe that'll work for you with your combination of versions?