That error is not relevant and can be ignored.
You should really update to 1.3.6 and run deluged and deluge-web to use the webui rather than the plugin.
Log file: rpcserver:303 Exception calling RPC request
Re: Log file: rpcserver:303 Exception calling RPC request
Well that means deluged is crashing, likely the ongoing crypto bug.
Re: Log file: rpcserver:303 Exception calling RPC request
You would need to get a backtrace to be certain why deluged is crashing. I mention the crypto bug because debian and ubuntu users are seeing this a lot but it is not a Deluge issue, it's in openssl library.
Re: Log file: rpcserver:303 Exception calling RPC request
Any news? Did the downgrade solve anything?