I'm guessing of course, but it sounds to me like nghayward has hit the nail on the head. If you use the 'Translate/Pull' tool on a hand it can drag the rest of the figure with it, thus moving the other hand. And like nghayward said the solution is to use the paramiter dials to move it. Another solution is to apply the 'Chain Break' to the relevant parts, in this case the hands and forearms. Chain Break will allow you to use the 'Translate/Pull' tool on a hand without the rest of the figure being draged along with it. Some body parts may require IK to be off before you can apply Chain Break to them.