InteropServices.COMException - Class not registered

I'm having some problems in using a type that comes from an old unmanaged DLL.

gobjDPProject = New DP_Store_21.cProject

When I make this assignment an exception is threw

A first chance exception of type 
'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll

Additional information: Retrieving the COM class factory for component with 
CLSID {98214FEB-FE5C-495F-A926-F23DC62EEDD6} failed due to the following 
error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 
(REGDB_E_CLASSNOTREG)).

To check the existence of this class I went to Regedit and found the component with the CLSID reported by the Exception, it exists and under the ProgID subFolder I can see the DP_Store_21.CProject class.

Inside Visual Studio -> My Project -> References I can navigate inside the DP_Store_21 DLL (it's an Interop) and the CProject class is there.

Run regsvr32 /pathTo DP_Store_21.dll gives no problems and the other classes of the library are correctly instantiated, what I am missing ?