Traceback (most recent call last):
File "/usr/bin/emerge", line 12, in ?
import portage
File "/usr/lib/portage/pym/portage.py", line 7235, in ?
init_legacy_globals()
File "/usr/lib/portage/pym/portage.py", line 7201, in init_legacy_globals
mtimedb = load_mtimedb(f)
File "/usr/lib/portage/pym/portage.py", line 7126, in load_mtimedb
d = mypickle.load()
cPickle.UnpicklingError: invalid load key, 'A'.
I can type emerge <anything I want here, doesn't matter> and I get the same thing after a delay of about 2-3 seconds.
If emerge --sync doesn't work, you could try to use a protage snapshot instead (see install handbook).
What did you do that broke emerge? I'm not judging (believe me I broke things more than I can count), I just need some background information before I can give a solid solution.