DBA Studio and TNS errors?

ORA - 12154 TNS: Could not resolve service name DBA Studio

I downloaded Personal Oracle 8.1.7 and extracted it to c drive on this windows 2000 pantium 4. I used the Database configuration Assistant to set up a database. I have checked my listener.ora and sqlnet.ora as well as tnsnames.ora - all seems fine. When I go into DBA Studio I cannot coonect to my database without having the TNS error.

I can connect system/manager in sqlplus ok.

pinged my machine ok.
net start showed me that listnere is running.

When I run tnsping service_name I get TNS - 03505 Failed to resolve service_name.

I have substituted the host with the actual ip address - no difference.

What is going on ??????

Help!!!!!!!!

Check the file name tnsnames.ora and make sure that it had been configured properly...

Sam

I have sorted the connection problem via sqlplus but still not via Dba Studio.

All I did to rid the error TNS - 03505 Failed to resolve service_name is : - I went into Net 8 assitant and created a service. This then created a tnsnames.ora in the network/admin directory for oracle with
AWGCDP1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = UKP-WNXY3XG69G2.mag.co.uk)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = awgcdp1.mag.co.uk)
)

this was the old one

AWGCDP1.MAG.CO.UK =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = UKP-WNXY3XG69G2)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = awgcdp1)
)
)

This led to success .........


AWGCDP1.mag.co.uk =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = UKP-WNXY3XG69G2.mag.co.uk)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = awgcdp1.mag.co.uk)
)
)

Thanks all!!!