Why is my java not working right on yahoo and pogo?

When I open up yahoo pinochle and sit at a table my java has a caution sign in the corner of the page. The cation sigh says java script when i put the curser over it. Some days I will be able to play with some slight mess ups. On other days the error wil cause my pc to crash. I have tried the java in two other browsers and it still acted up. Is there anyone out there that could help me with this problem. I have already uninstalled and reinstalled the program several times. Odd thing is that I don't get the error on all yahoo games. So far I have tried canasta and I had no erroe over there.