The Villager ID of 10 is taken by Agricraft already.

Both with default configs crashes client to desktop while loading.

I changed the ID of the RFtools villager to 0, however this produced the same result.

I changed the agricraft villager ID to 56, and it started up fine.

This is not really a bug. No matter what ID I make default in rftools there is always a chance of conflict. So just a matter of configuration

Or you know, it could be a feature request, auto assigning IDs?

Actually RFTools automatically scans for the first available ID by default. Problem is that Agricraft doesn't and apparently takes its villager after RFTools does.

They actually added that a day or so ago.