When upgrading from Ubuntu 12.04 to 14.04 I had a strange failure. I have done 4 OpenERP servers and the last one gave me this error.

It occurs when trying to print anything sales or purchase related. Product labels can be printed.

This is the message it shows:

cannot concatenate 'str' and 'int' objects
handle_pageBegin args=()
 

I have made a backup of my database and tried removing all fields I create myself. I also removed all changes to views I made. When googling for this problem, it only gave me python related errors.

EDIT: I also tried installing werkzeug 0.8.3 version, but that made no difference. On my other server this worked like a charm.

This is what openerp log shows.

2014-09-01 06:19:04,070 14588 ERROR TMC-2 openerp.netsvc: cannot concatenate 'str' and 'int' objects
handle_pageBegin args=()
(<type 'exceptions.TypeError'>, TypeError("cannot concatenate 'str' and 'int' objects\nhandle_pageBegin args=()",), <traceback object at 0x7f3c5dbbcb48>)
Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.7/openerp/netsvc.py", line 296, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/usr/lib/pymodules/python2.7/openerp/service/web_services.py", line 654, in dispatch
    res = fn(db, uid, *params)
  File "/usr/lib/pymodules/python2.7/openerp/service/web_services.py", line 760, in exp_report_get
    return self._check_report(report_id)
  File "/usr/lib/pymodules/python2.7/openerp/service/web_services.py", line 738, in _check_report
    netsvc.abort_response(exc, exc.message, 'warning', exc.traceback)
  File "/usr/lib/pymodules/python2.7/openerp/netsvc.py", line 71, in abort_response
    raise openerp.osv.osv.except_osv(description, details)