Hi
1. Make sure that the correct Field is bound to the Text box. (that its not blank)
2. Make sure that you are not getting any errors (if it errors out it will not show anything)
3. Manually verify that what you are putting in matches.
You are doing a lookup, so you should be able to easily do this
Add another label.
In the Text do not take the values from the dropdowns/text instead hard code it
LookUp('Salary Information', Title = "DP" And Scale = "2")
Or
LookUp('Salary Information', Title = "DP" And Scale = 2)
If Scale is a Number then make sure to convert it to a number, OTHERWISE if you put in a string, it will essentially fail, but not always tell you.
If you are unsure then put 2 more labels, and put one with a number 2 and one with a string 2 and see which one errors out.
If it does NOT show you any data, then you know its an issue with your data in the back end.