ODP.NET

Hello everyone !!

I know that the same problem has been posted previously by other users. I've tried every solution that is suggested but it still don't solve my problem. Here is the detail :

Environment : Window 7 Home Premium 64 bit
Database : Oracle 10g Express Edition
ODAC version : Oracle 10g Release 2 ODAC
Microsoft Visual Basic 2005 Express Edition

I've been trying codes and every time I execute it, the same error will appear :'An unhandled exception of type 'System.NullReferenceException' occurred in oracle.dataaccess.dll
Additional information: Object reference not set to an instance of an object.'

Reading the previous post, so I tried to run both Oracle & Visual Basic 2005 as administator, checked the status of service, tnsping the database aliases in tnsnames.ora , log on through sqlplus with the user provided in connection string :: all these are succcesful. Still, when I tried to run my application in Visual Basic, the same error appear.

The codes that I've been using:


Imports Oracle.DataAccess.Client
Imports Oracle.DataAccess.Types 'declaration in General class

Dim conn As New OracleConnection("user id=userID;password=mypassword;data source=My-PC:1521/XE")
conn.Open()



I've also defined a database alias in tnsnames.ora file :

OraDb=
(DESCRIPTION=
(ADDRESS_LIST=
(ADDRESS=(PROTOCOL=TCP)(HOST=My-PC)(PORT=1521))
)
(CONNECT_DATA=
(SERVER=DEDICATED)
(SERVICE_NAME=XE)
)
)


Is it because of I'm using a 64-bit Windows platform?? Thanks in advance.