Issue with sending JSON data from VBA - json

Question

I am trying to create an Excel macro to send cell data to a URL using a POST request. I have chosen to format that data using JSON, because there is a lot of it to send. Here is my code for sending the JSON:
Dim jFullDictionary As New Dictionary ' This dictionary contains a Collection
...
Dim JsonURL As String
JsonURL = "http://myurl.com"
Dim JsonHTTP As New MSXML2.XMLHTTP
Set JsonHTTP = CreateObject("MSXML2.XMLHTTP")
Dim JsonString As String
JsonString = JsonConverter.ConvertToJson(jFullDictionary, Whitespace:=3)
With JsonHTTP
.Open "POST", JsonURL, False
.setRequestHeader "Content-type", "application/json"
.setRequestHeader "Accept", "application/json"
.setRequestHeader "User-Agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)"
.send JsonString ' This is where the program breaks
End With
Every time I run this, I get the error that says (something along the lines of)
Run time error: Could not find the resource specified
I have already looked at these StackOverflow threads, but I've gotten nowhere:
Error from VB excel macro code - msxml3.dll -2146697211 The system cannot locate the resource specified
Sending JSON POST request in VBA
Additionally, I have tried installing Tim Hall's project from here, but the installation doesn't work on my machine (might be because it's a work computer).
The error makes me think that it has something to do with the resources that I have loaded, but I'm not sure. If it's not that, then there is something wrong with my code. Any help would be appreciated, thank you.
Edit:
Here is the loop that I use to fill the jFullDictionary with my data:
Dim jDictionary As New Dictionary
Dim jCollection As New Collection
Dim jFullDictionary As New Dictionary
For i = 1 To excelRange.Rows.Count
For j = 1 To excelRange.Columns.Count
jDictionary("row") = i
jDictionary("name") = Cells(5, j) ' This assignment is arbitrary
jDictionary("value") = Cells(i + 1, j) ' so is this
jCollection.Add jDictionary
Set jDictionary = Nothing
Next j
Next i
jFullDictionary.Add "parametersList", jCollection