Oracle Database Discussions

Hi, this is for the 1st time i have installed oracle 10g on my laptop with windows vista on it.
I can connect through Oracle SQL* Plus by giving the following credentials :-

Username : sysman
Password : password
Host String : vijay

But when i tried to open iSQL*Plus by entering the following URL:-
http://rajeev-pc:5560/isqlplus/login.uix

And putting the same credentials as above, i'm not getting connected and it is giving me following error :-

ERROR - ORA-12154: TNS:could not resolve the connect identifier specified

I have checked the TNS entry. I can see, it is there in it.

VIJAY =
*(DESCRIPTION =*
*(ADDRESS = (PROTOCOL = TCP)(HOST = Rajeev-PC)(PORT = 1521))*
*(CONNECT_DATA =*
*(SERVER = DEDICATED)*
*(SERVICE_NAME = vijay)*
*)*
*)*

But still giving me such error.
Please tell me. I do not know much about it. Please help me to resolve this issue.

Thanks in advance for your precious time...:-)