The specified module could not be found. (Exception from HRESULT: 0x8007007E)

Revision 2
Hi now i am using sqlite for windows forms but while running the project it is showing the error----Unable to load DLL sqlite3. The specified module could not be found. (Exception from HRESULT: 0x8007007E);

i had added the dll of system.data.sqlite.dll...but it is showing the same error...so please any one help me by giving the perfect answer regarding this problem....thanks in advance

MY connection string:

 Private sql_con As New SQLiteConnection
sql_con = New SQLiteConnection(Data Source=D:\iact\Data_Main.sqlite;Version=3;New=False;Compress=True;)
       sql_con.Open()

Thanks
Pallavi