Error in ctrlp#init

[gilligan]

Calling :CtrlPSymbol yields the following messages

Error detected while processing function ctrlp#init...ctrlp#setlines..ctrlp#symbol#init:
line 2:
E715: Dictionary required
Error detected while processing function ctrlp#init..ctrlp#setlines:
line 7:
E706 : Variable type mismatch for : g:ctrlp_lines

Just for reference this is my ctrlp configuration:

"
" ctrlp setings
"
let g:ctrlp_working_path_mode = 2
let g:ctrlp_root_markers = ['.git','.project_root']
let g:ctrlp_user_command = ['.git/', 'cd %s && git ls-files']
let g:ctrlp_clear_cache_on_exit = 1
let g:ctrlp_custom_ignore = {
  \ 'dir':  '\.project$\|\.metadata$\|\.git$\|\.hg$\|\.svn$',
  \ 'file': '\.exe$\|\.so$\|\.dll$|\.dylib$',
  \ }
let g:ctrlp_extensions = ['symbol']

[mattsacks]

It's an issue with the syntax of some files. What's the output of :echo &ft in the file this errors out?