Peculiar Character Sheet Error - Syntax?

This week's game, a player had to take over someone else's character and play them in addition to their own.  When they tried to roll initiative the error attached turned up: I have no idea how to put this right, or what may be wrong with it. He also gets the same sort of error message when he tries to roll for the character's weapons. I can't reproduce this error myself as it works for me as GM.

Did. You give them control rights for the character? Or were they just using macros that were made globally available?

I gave them control rights for the character. I didn't know it was possible for people to control another's character in any other way.  We do this quite often, because I won't cancel a game if one person is unable to play. That way lies madness.

ok, other question. Did the user open the character sheet, or just use shortcut macros?

I'm 98% sure the user opened the character sheet. He's not someone who would know a macro if it bit him in the b**. 

Haha! Hmm, ok. That's definitely odd then. I'll try to thiof some other possibilities, but at the moment I'm stumped. I'd recommend sending a bug report in via the help center.

OK, I've sent a request for help to Roll 20. Thanks!