If the field is being set anyway then the If is not properly evaluating but it looks correct as listed. Is NEW RADIO LOG a related table? If the record being set is a related field, your current table can only see the first related record and will set that.
Anyway, if you do not have Advanced, you can use Custom Dialog to see what error is thrown.
If [NEW RADIO LOG:: From (not = to (the little = sign with the stroke through it) "VMR466"
Set Error Capture [ On ]
Set Field [NEW RADIO LOG::To; "VMR466"]
Show Custom Dialog [ OK ; Get ( LastError ) ]
... Check your Set Field step. Set Field has two parts and it is one of the most normally mis-specified script steps. The first part Specify Target Field (and here you select the field to set) and the second part, Calculated Result (and here you only type the calculation of "VMR466"). I might also suspect that something else is in the field, such as a space (which will throw off the match).
I worked it out, what i did was to select on exit in the script trigger and it worked. Thanks for the reply once again. You have a great day.