Ugh. It refuses to load most of my builds.. 
You likely are trying to load builds that require brick add-ons that are not enabled by the server. BuildBot will do the best it can to work around those missing bricks.
I am considering adding a supplemental to the current save system that also saves the X Y and Z dimensions of all the bricks currently in the server when the build is saved, and that can be used to verify what brick to use, and to help BuildBot come up with a possible replacement brick if the exact datablock does not match. This is not very likely to be added.