I'm trying to use a toolbar that was developed by the EPA for BMP siting (see below link). The download seems like it should be fairly straightforward, an executable (BMPSitingTool_Setup.msi) is run and the toolbar is downloaded to the Program Files x86 folder within my C-drive. The BMP siting tool comes with a host of .dll, .tlb, .olb, etc files. According to the installation instructions, once I open a new ArcGIS map, it should find this new toolbar automatically and it should show up under Customize > Customize Mode. It doesn't. I've tried doing "add from file" and manually selecting the .tlb file but I get a message of "can't load type library from specified file" followed by "no new objects added". Any idea what's causing this? I'm on ArcGIS 10.3 and the tool was developed within ArcGIS 10.1, but I didn't think there were any compatibility issues with later versions of ArcGIS.
Edit: I've verified that I have administrator privileges on my computer.