hg notify error

[John Turner]

I attempted a push to my central repo and the notify hook raised the  
following error:
   changegroup.notify hook raised an exception:
  invalid literal for int() with base 10: '300 # max lines of diffs to  
include (0=none, -1=all)'

My mercurial.ini file is using the following notify settings:
[notify]
sources = serve push pull bundle
test = False
maxdiff = 300
template =
   details:   {webroot}/rev/{node|short}
   branches:  {branches}
   changeset: {rev}:{node|short}
   user:      {author}
   date:      {date|date}
   description:
   {desc}\n

Have I neglected something or is the syntax awry?