c# 4.0 - Unable to add reference to rzdcx.DLL in C#.Net 4.0 visual studio -

i trying send dicom file remote ae, seems done instantly dcxreq object , send method rzdcx.dll, however, didnt work when trying add rzdcx.dll reference, says please make sure file accessible, , valid assembly or com component, possible ways fix problem in order add reference??

so far have tried dllimport, object dll cannot created. [dllimport(@"c:\users\kevin eger\documents\visual studio 2010\projects\realdicomserver\realdicomserver\bin\debug\rzdcx.dll", entrypoint = "dcxreq")] public static extern void send(string localae, string remoteae, string ipa, int portn, string filepath, string succeededfileslist, string failedfilelist);

    static void main()     {         string s = "";         string f = "";         dcxreq requester = new dcxreq();         requester.send();     } 

rzdcx.dll com object. develop have regsvr32 it. command line admin rights following: regsvr32 rzdcx.dll

for distribution can check in references "isolated com" rzdcx can used in user mode , users don't have regsvr32