"Object required" - path string unrecognized in windows scripting file

I'm writing a wsf that opens a csv, reads the contents and prints them like so:

<job id="Test_Script">
   <script language="VBScript">

    Dim objFSO, strSourcePath, strSourceFile, objInFile, strData    

    Set strSourcePath = "C:\test\ERACSV\"
    Set strSourceFile = "Payments.csv"
    Set objFSO        = CreateObject("Scripting.FileSystemObject")   
    Set objInFile     = objFSO.OpenTextFile(strSourcePath & strSourceFile, 1, False)
    Set strData       = objInFile.ReadAll
    objInFile.Close

    WScript.Echo strData
   </script>
</job>

I keep getting this weird error:

Script:  C:\Users\myuser\openCSV.wsf
Line:    4
Char:    4
Error:   Object Required '[string: "C:\test\ERACSV"]'
Code:    800A01A8
Source:  Microsoft VBScript runtime error

It seems weird because why is the object it requiring a string I've already defined?

Solution

Set in VBScript is only for "object-types" (COM Objects, etc), but String values are not "objects" (as far as VBScript is concerned), so don't use Set.
- You can either remove the Set keyword but otherwise keep the assignment statement as-is, or altenatively use the Let keyword instead of Set: Let is for non-object values (including Strings, but also Integers and Doubles).
In VBScript, when calling a Function (or COM Method) that returns a value you need to specify parentheses, you only omit the parentheses when calling a Sub (i.e. a void function or method) (unless you're using the Call statement), in this case TextStream.ReadAll() returns a String value.
Use the named-constant ForReading instead of the magic-number literal 1.
You also should add Option Explicit at the first-line of your script, otherwise VBScript won't care about variable declarations (indeed: objOutFile is declared, but objInFile is what's actually used....)

<job id="Test_Script">
   <script language="VBScript">

    Option Explicit

    Dim objFSO, strSourcePath, strSourceFile, objInFile, strData    

    Let strSourcePath = "C:\test\ERACSV\"
    Let strSourceFile = "Payments.csv"
    Set objFSO        = CreateObject("Scripting.FileSystemObject")   
    Set objInFile     = objFSO.OpenTextFile(strSourcePath & strSourceFile, ForReading, False)
    Let strData       = objInFile.ReadAll()
    objInFile.Close

    WScript.Echo strData
   </script>
</job>