It wasnn't the code altering that all said it is, because it didn't work for me.
I just installed that mootools you said, enabled it from the tab options, and it still didn't work, until I also changed display type to rounded div, maybe something else works. it's 4 AM, you owe me a beer.
No, it wasn't that, I think iti was the fact that I disabled override options from the Gallery Tab options. I also see in the status bar that it accesses a web site called Ytimg.com
maybe it is not always on or responding. I am eager to see the answer of someone that really understands coding.