If the client has any component of MS Office installed (Word, Excel,etc.), Front Page, Microsoft Project, etc, etc, then they should have the DLL on their machine, in which case you do not need to distribute anything relating to this DLL.
MS Forms is installed with any Office project; It is not listed in the VB redistribution list; It falls under the cat. of Microsoft Shared - Vba files; Strange enough I found a duplicate of the DLL in my VB6 directory;
It is even installed with Microsoft® Office XP or Microsoft Office 2000.
As hard as I normally am on an issue like this, I am not worrying about it too much in this case. It is not like your installing an interface to another MS application files (xls, mdb, etc) and the user doesn't have a licenced version of the Application installed.
Another way of making a colored border around a ComboBox or Text box is to create a Shape a little larger than the Text box and set its' fill color (works great - been doing it for years).