You're probably using YMSGv102 which doesn't allow photoshare.

Sign out of Yahoo! Messenger;
Go to the YTK Control Panel, Security (spider web icon), "Auto-Reconnect Protocol Version" change it to 15 if you're still using Yahoo! Messenger 8.1

Alternatively you can sign out of Yahoo! Messenger and uncheck "Auto-Reconnect".

Also you may want to look at this since it seems you're having a lot of difficulties;
http://www.ytk.smfnew.com/index.php?topic=148.0