I have been running Zimbra open-source version in a trial for 4 months and it is, basically, the biz but I have the following problems:

1) The school I work at can get exchange cals for 5 pounds (about $7.50) via a local authority bulk purchase scheme and we can't afford that so the network edition is way out of our league.

2) I've tried, on many occasions to back up the OSS edition but have had no success. I've search with Google and read and followed the WIKI backup example, made sure that I had the same version and built a second PC, installed the same OS version etc.

I backed up the original zimbra folder onto CD using tar and preserved permissions etc. in the process, but it always seems to keel over, sometimes complaining about LDAP problems and at others just dropping out after the first service starts.

I really do want to go with Zimbra as it's been so reliable so far and I don't miss restarting the exchange box everytime it dies

Any help with detailed procedures would be greatly appreciated.