Ctrl/Alt Keys not working properly

Hello fellow multi-boxers,
I've been multi-boxing for quite some time now and since the last patch have had a number of problems. I use a mac pro desktop and the latest problem I'm having is that the ctrl and alt keys are not working properly. It's a weird problem really, I have a macro on my main toon, which is a lvl 80 hunter, for the mount. I use alt to use the lower lvl mount for when I'm slaving lower lvl toons through dungeons and whatnot. Recently, the alt key has stopped working for one of the slaves, while the ctrl key stopped working for another. Otherwise I would have just switched modifiers, which I did and is how I found this particular problem. I use the plexer software and don't have any keys except "Z" on the ignore list. Hopefully someone can help me out here.......it's becoming rather tiresome really, the last patch really screwed the mac using community!

Thanks for any help.

Just to clarify, the alt key is working for some of the toons, but not all of them.
And similarly, the ctrl key works for some, but not all.

So the key is being broadcast.
Not sure that the keys are broadcast to all clients.
And not sure on the workaround if it is not.

However, you could try the macro:
/cast [nomod] Big Mount; [mod] Small Mount

That way, you just need any mod key, or the absence of mod keys for the macro.
That of course assumes, at least one mod key is working for each toon.

The macro I'm using has 3 mounts on it:

#showtooltip
/use [nomod] Armored Brown Bear; [mod:alt] Grand Ice Mammoth; [mod:ctrl] Purple Hawkstrider

I have 4 slaves and 2 of them have no problem mounting themselves no matter which modifier is used. The other 2 are the ones I'm having trouble with. One of them, the alt key will not work but the ctrl key will. The other one is the reverse. I've tried having either of those toons as the active window when using the macro on the main and clicking the icon and that doesn't work either. So I'm not all together sure that it's a broadcast issue. It's like the key itself is not working in the instance of WoW. I've not experimented too much, I just click using the modifier for the mount I want to use then really quickly click w/out a modifier so that the toon that isn't mounting will while the others just say that another action is in progress. Everyone mounts......just wondering if anyone else had run across anything similar. And of course once they hit 40 I won't need the hawkstrider =D . Thanks for the input.

What program are you using to broadcast your keys?

I'm using Plexer.