you're right, that's a bug in the Yahoo plugin of 0.12. It's already fixed in svn and will be fixed in 0.12.1.
That problem was fixed lately. Please use the svn version or wait for the 0.12 final. It will be released soon.
The Yahoo protocol changed slighty after Kopete Beta1 was released, which made the Yahoo login fail. This was fixed in Beta2.
Webcam sending over Yahoo! is implemented just in the 0.12 series of Kopete. You'll have to compile the beta2 or wait for the 0.12 final which will be released later this month.
That is a regression in kopete 0.12. I simply forgot to add it to the new Yahoo implementation. The option will be there again in the 0.12 final version.
