editing /var/lib/dpkg/available

[Waqqas Dadabhoy <waqqas@waq.dyndns.tv>]

I played around with Zimbra a while ago, but have removed it now. I
get the following error whenever I use apt-get:

warning, in file '/var/lib/dpkg/available' near line 8727 package 'zimbra-ldap':
 error in Version string '6.0.8_GA_2661.DEBIAN5_64': invalid character
in version number

Since I won't be using Zimbra again, I am considering removing the
Zimbra-related lines from /var/lib/dpkg/available. To me the
hand-editing seems crude, is there a 'more clean' or 'recommended' way
to get rid of the error?

Thanks.