SQL nav 6.5 and oracle client 10g error

I'm getting the following message when I try to open sql nav. Please see attached image. I have verified the tnsnames.ora file is under ORACLE_HOME\network\admin.

Any help will be appreciated.

Hi Luan,

I believe it is the same issue as reported in - http://sqlnavigator.inside.quest.com/message.jspa?messageID=125467#125467

Is your envi Windows 7? Please note SQL Navigator can ONLY work with Oracle 32 bit client. Please confirm if you Oracle 32 bits client installed.

If you already have the 32 bit client installed and still get that error.
The AV occurs because you dont have the path of your tnsnames.ora in TNS_ADMIN system variable, it might be currently blank. This is an known issue, we have fixed the AV in the next release v6.6. In v6.6 you can start up SQL Navigator without the AV but no connection allowed until you set up the TNS_ADMIN path correctly.
Could you please update the TNS_ADMIN to point to the location of tnsnames.ora and try again.

Please let us know how you go.

Thanks and regards,
Bruce