Brabbel chokes

[toirl]

Unter some conditions brabbel chokes and fails to parse the expression with the result of a alrge amount of error messages.
This is only a short excerpt of the traceback. This traceback goes over many screens.

[:error]     return self.expr._parse( instring, loc, doActions, callPreParse=False )                                                                                              
 7741 [:error]   File "/usr/lib/python2.7/site-packages/pyparsing.py", line 946, in _parseCache                                                                                         
 7742 [:error]     value = ParserElement._exprArgCache[ lookup ]                                                                                                                        
 7743 [:error] KeyError: ({{FollowedBy:({Forward: {{FollowedBy:({Forward: {{FollowedBy:({Forward: {{FollowedBy:({Forward: {{FollowedBy:({"not" ...}) Group:({["not"] ...})} | {Suppress:      ("[") [{string enclosed in single quotes | Combine:({["-"] W:(0123...)})}] [, [{string enclosed in single quotes | Combine:({["-"] W:(0123...)})}]]... Suppress:("]")} | Combine:(      {["-"] W:(0123...)}) | string enclosed in single quotes | Combine:({"$" W:(abcd...)}) | "True" | "False" | "None" | {W:(abcd...) Suppress:("(") Group:([{{{{{{Combine:({["-"] W:(0      123...)}) | string enclosed in single quotes} | Combine:({"$" W:(abcd...)})} | {{Suppress:("[") [{string enclosed in single quotes | Combine:({["-"] W:(0123...)})}] [, [{string e      nclosed in single quotes | Combine:({["-"] W:(0123...)})}]]...} Suppress:("]")}} | "True"} | "False"} | "None"} [, {{{{{{Combine:({["-"] W:(0123...)}) | string enclosed in single       quotes} | Combine:({"$" W:(abcd...)})} | {{Suppress:("[")  ....

This error currently only occurred when triggering brabbel from a web application more the once in a short time (E.g by clicking multiple times on submit).

Currently the reason for this is not known and must be examined.