Yes , it is possible to find if someone has blocked you on Gtalk by a great little instant messaging utility, Pidgin .
You first need to configure Pidgin with your GTalk account and believe me after seeing Pidgin features you will be compelled to switch to Pidgin . If you are not sure how to configure Pidgin with Gtalk , read about this here .
Ok, now when you are aware of how to configure Pidgin to work with Google Talk, I’ll guide how to make smart use of Pidgin to identify who has blocked you on Google Talk.
It’s very simple. Just follow the steps:-
1- Log in to your Gmail account on Pidgin.
2- Go to “Buddies” -> “Show Offline Buddies“. (A person who has blocked you must be showing offline to you. So you need to make all offline friends visible)
3- Now all your contacts are visible to you. Pick any one of those.
4- Right Click on your chosen contact name and select “Get Info“. ( Names And Id Hidden due to Privacy Implications )
It will show you the brief information of your contact. Now, if any of your contact has blocked you on Google Talk, you will not be able to see his/her profile.
6- Select a contact who you think may have blocked you. Again, Right Click on his/her name and select “Get Info“. You will not see anything. Not even the contact’s name. ( Names And Id Hidden due to Privacy Implications )
This shows in turn that the following contact has blocked you and doesn't wish to talk to you . Solve out your problems soon. :P