When I use the version 6.04 configuration program I get the following error when trying to read the configuration: 'default config file not updated use the file dated 30Jan2003'. Then the configuration program closes and will not go any further.

The MultiVOIP serial configuration software is firmware-specific, meaning you must use the software version that exactly matches the version of firmware currently loaded on the MultiVOIP. Using 6.04 configuration software on an MVP210 not running 6.04 firmware may cause problems similar to what you describe.

If you know the VoIP's IP address, you can Web into it from a computer on the same network to determine what firmware version it is running. The Web interface requires that you use a current browser with the necessary Java plug-in installed. The required Java plug-in is included on the CD that ships with the MultiVOIP's. Alternately, it can be downloaded from our ftp site at https://webfiles.multitech.com/multivoip/misc/java/j2re-1_4_2_01/.
Download the j2re-1_4_2_01-windows-i586.exe you find at this location to a clean directory on your hard drive and double-click the icon it creates to install the plug-in.
You must reboot your computer once the installation completes (the software will not prompt you to do so, but Internet Explorer requires it).
Open your browser and type the MultiVOIP's IP address in the address bar to access configuration.
Once the configuration comes up, you can go to Configuration ->System Information to determine MultiVOIP firmware version.
Once you have determined the firmware version, you can download the serial configuration software to match from https://webfiles.multitech.com/multivoip/.
The file name will be mvpxxx.exe, where xxx matches the voip's firmware version (e.g. the file name for the software corresponding to firmware version 6.07 is mvp607.exe). You should be able to make any configuration changes via the Web interface, so downloading the serial configuration software may not be necessary.