This error can occur on either of the VMware Update Manager plugin or the VMware Converter Enterprise plugin for VirtualCenter, when installed manually or as part of a complete install.

This also happens with VMware vCenter Converter:

Event Type: Error
Event Source: MsiInstaller
Event Category: None
Event ID: 10005
Description:
Product: VMware vCenter Converter -- Error 25089.Installer failed to register vCenter Converter with vCenter server.
Data:
0000: 7b 36 45 36 33 45 36 32 {6E63E62
0008: 31 2d 43 45 38 36 2d 34 1-CE86-4
0010: 46 31 42 2d 38 32 36 38 F1B-8268
0018: 2d 43 31 36 31 42 31 45 -C161B1E
0020: 32 35 45 34 31 7d 25E41}

The Administrator password used in the install contains non-alphanumeric characters such as space, dash or exclamation.

Change the Password to be all alphanumeric for the duration of the install. e.g.

Password1

http://communities.vmware.com/thread/117388

VirtualCenter Consolidation Service Usernames and Passwords Must Use Only ASCII Characters
http://kb.vmware.com/kb/1003096

VirtualCenter Database Upgrade Fails with an Exception When a Password that Contains Apostrophes or Double Quotes Is Used
http://kb.vmware.com/kb/1003049