Using OTAClient.dll with c#

Hi,

   I want to use the librairy OTAClient.dll for a c# project (using sharpdevelop). I have found the dll (=> C:\Users\xxxx\AppData\Local\HP\ALM-Client\qualitycenter11-mar).

I have added it as a reference (Add reference, Assembly browser, Browse, ...). "OTAClient" appears in my list of references. OK
At this point i was expecting to be able to use it : but the name space "TDAPIOLELib" is not found. Am i missing something.

Thanks.