i think that the last thing i did before saving it was adding the constraints to the top and to the lower shelf... and it saved fine. didn't try to change materials or anything at that time though. it was when i re-opened it, and ever since then, that the crashes have happened.
as it is now, i have managed to recreate the cabinet, and it seems to be working fine. thankfully you can save your part editor cuts as a pattern and re-apply them

that saved me a whole chunk of time.
thanks again for checking it out
oh, Todd, got your voicemail, but i think this should explain everything better than what you would be able to get from me trying to yell over the noise of the shop on the phone (my computer for ecabs is right beside the router in the middle of the shop, so they can have me run both at one time)

let me know if you need any more info.