Sorry, I misread your original post. Try this.
if ((%abc != $true) && (%cbs != $true)) {
This will not execute if either variable is set to $true. With this you could either unset the variables or set them to anything except $true.
You could also try this
if ((%abc != $null) || (%cbs != $null)) {
This would trigger if either variable is set with any value at all.
Last edited by RoCk; 11/05/08 05:34 PM.