Is there a traceback printing in counterpartyd.log? If so, that would probably have a line number to the error. If it's something we haven't fixed, we'll get it fixed once we know the location (given that you said you already patched the bug we already fixed).
This is in the api.error.log:
[14/Apr/2014:10:20:11] HTTP Traceback (most recent call last):
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/cherrypy/_cprequest.py", line 656, in respond
response.body = self.handler()
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/cherrypy/lib/encoding.py", line 188, in __call__
self.body = self.oldhandler(*args, **kwargs)
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/cherrypy/_cpdispatch.py", line 34, in __call__
return self.callable(*self.args, **self.kwargs)
File "/home/jeremy/counterpartyd_build/dist/counterpartyd/lib/api.py", line 445, in index
response = JSONRPCResponseManager.handle(data, dispatcher)
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/jsonrpc/manager.py", line 47, in handle
request = JSONRPCRequest.from_json(request_str)
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/jsonrpc/jsonrpc.py", line 22, in from_json
return JSONRPC10Request.from_json(json_str)
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/jsonrpc/jsonrpc1.py", line 93, in from_json
method=data["method"], params=data["params"], _id=data["id"]
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/jsonrpc/base.py", line 12, in __init__
self.params = params
File "/home/jeremy/counterpartyd_build/env/lib/python3.3/site-packages/jsonrpc/jsonrpc1.py", line 57, in params
raise ValueError("Incorrect params {}".format(value))
ValueError: Incorrect params {'filters': [{'field': 'address', 'value': 'addressRedacted', 'op': '=='}]}
Eh...unfortunately not very helpful, due to the nature of that error. We'll have ouziel find and fix this 'a' bug in master tomorrow morning first thing (as well as a counterwallet mobile bug Swarm was having problems with).