Hello and welcome Oh!
When you use a TextBox control e.g. Microsoft Forms 2.0 TextBox, its Text property (e.g. textBox1.Text) will have the text (string) entered by a user. Because you are expecting an Integer (or Float) value here, you need to do some kind of input validation and the internet has many different suggestions on how to do this (search e.g. for "VBA cast integer to string" without double quotes).
With a ProcessBook display, there is no collection of PBValue symbols but a collection of symbols. With other words, you iterate through the collection of symbols and check if they are of type PBValue.
Dim sym As Symbol For Each sym In ThisDisplay.Symbols If (sym.Type = pbSymbolValue) Then If (sym.GetValue(Time, 1) > compVal) Then MsgBox sym.Name & " => Ok" Else MsgBox sym.Name & " <= Bad" End If End If Next