The following Microsoft Graph api is one of many that does not have a body, but does expect the content type to be set toe application/json

I think that in cJsinbHttpTransfer.pkg this should be fixed:
   Function HttpVerbJsonAddrExec String sHost String sFilePath Address aJson Integer iLen String sVerb  Returns Boolean        Boolean bOk
        Integer iError
        String sContentType
        Send ClearDataReceived  // this should be zero, just in case it is not
        Set psRemoteHost to sHost
        // You need to clear headers between posts. If you need to set custom headers you should
        // set pbClearHeaders to false and then manually send ClearHeaders and AddHeaders in your code
        If (pbClearHeaders(Self)) ;
            Send ClearHeaders
        Get psContentTypeSent to sContentType 
        If (iLen > 0 and sContentType <> "") Begin
            Get AddHeader "Content-Type" sContentType to bok
        Get HttpVerbAddrRequest sFilePath aJson iLen False sVerb to bOK
        Function_Return bOk
Obviously iLen would be 0, and thus it does not set the content type. I think that the "If (iLen > 0 and sContentType <> "") Begin" should be changed to "If (iLen > 0 OR sContentType <> "") Begin"

btw the error returned is:
{  "error": {
    "code": "BadRequest",
    "message": "A supported MIME type could not be found that matches the acceptable MIME types for the request. The supported type(s) 'application/json;odata.metadata=minimal;odata.streaming=true;IEEE754Compatible=false, application/json;odata.metadata=minimal;odata.streaming=true;IEEE754Compatible=true, application/json;odata.metadata=minimal;odata.streaming=true, application/json;odata.metadata=minimal;odata.streaming=false;IEEE754Compatible=false, application/json;odata.metadata=minimal;odata.streaming=false;...
Kind regards