Anyone got any ideas how to fix this?

AT&T / Cingular I would imagine ey? Or is it from a software point of view?

what exactly is the problem with the mute button?

I personally find Bold mute button harder to press than Curve mute was, but mine's not broken. It seems the angle that you press it from on Bold has to be more direct than it did with Curve.

I got a little problem with my Bold's mute button too. Sometimes it works, sometimes it don't. Not really a problem when I can't get it on 'stand-by', but a BIG DEAL when I can't get it out of 'stand-by'...

Is this a general Bold issue? Do I have to press it exactely the right way (like my wife...)? Or does it need repaired?

I had the same issue. i had to press it so hard... So I just took it to att, and they took me to repair shop, and they swaped my device with a new one! BRAND NEW, not a refurbished. They are finding that there is a hardware problem with that mute / silent button...

My new one isn't having issues, sooo far...

Mine had issues but is working perfectly after my Bezel swap!