A lot of internal changes have been made since 1.6. You'd most likely be better of with rewriting the mod instead of updating the mod.
BuildCraft is now using the Forge energy capability (or is it still using the RF API?).
I'd recommend putting the files through a json validator(I use http://jsonlint.com/). It should point out the location of the error, from that you can usually find the issue within a few seconds.