I have this problem also. I suspect you have installed IC2 and playing on a world created with IC. Many items have had their block ids changed so:
Tin Ore = Unnamed pink block, that drops Reinforced doors, when broken.
Copper Ore = generator.
I'm going to look for a world editor so i can change them over. (I hope it exists)
Change IDs ### to ###
---------
Copper Ore 246 -> 249
Tin Ore 229 -> 248
EDIT: I had cables turn into sticky resin, solar panels into reinforced glass and many more. What a (BEEP)ing nightmare!! 