Rails 3.1 rake assets:precompile failing

Anyone seen this befor开发者_运维百科e? If not, any good tips on debugging rake issues w/ no stack trace would be appreciated!

My site's running fine in dev, since assets are not compiled, but the compilation of my assets is failing, and I'm not getting a useful stacktrace, even w/ the --trace flag

All I'm seeing is:

rake assets:precompile --trace 1 ↵ ** Invoke assets:precompile (first_time) ** Execute assets:precompile rake aborted! undefined method `gsub' for nil:NilClass

Any suggestions? Thanks -jeff