error message when trying to uninstall

I need to uninstall Avast from my computer and everytime I try I get this message “A setiface error has occurred: 53687029” and then it tells me to reinstall or contact support. Help me please!!!

Your installation appears to be corrupt so you will nee to use the Uninstall Tool from safe mode.

Download the avast! Uninstall Utility, find it here and save it to your HDD.

    1. Now uninstall (using add remove programs, if you can’t do that start from the next step), reboot.- 2. run the avast! Uninstall Utility, reboot. If step 1 failed it will be necessary in your case to run this from safe mode, once complete reboot into normal mode.- 3. install the latest version, reboot.

Booting into safe mode http://www.pchell.com/support/safemode.shtml

Which is your old antivirus? How did you uninstall it to install avast?