I've been running into this issue as well. Up until now I was able to use 1388 because none of the mods used required a later version, but I tried adding a few new ones and they don't work with 1388.
Is the following log sufficient? It's what the Technic Launcher console logs for my modpack. The fml-client-latest.log was a bit too big for pastebin (and I only have a few minutes to post this ), but maybe this one contains enough info?
http://pastebin.com/v50kfnKy
If not then let me know, I'll upload the bigger log somewhere else.
