Charging is a full-round action, unless you are for some reason restricted to a Standard action (as in a surprise round), in which case you can charge as a standard action, but only out to your regular move distance.
To the best of my knowledge, this is not a house rule. Maybe the rule is intended only for cases like a Slow spell, but I think it applies here, too. That's why I let Ery charge.
Regardless, we'll go with it for now and I'll carry on. I don't expect the bugbears to survive the round, honestly.