ACT Web Server returns 500 when headers are duplicated

[EQAditu]

System.ArgumentException: An item with the same key has already been added.
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at Advanced_Combat_Tracker.FormActMain.ActWebConnection.ParseHeaders()
at Advanced_Combat_Tracker.FormActMain.ActWebConnection.ProcessGet()
at Advanced_Combat_Tracker.FormActMain.ActWebConnection.ProcessRequest()
at Advanced_Combat_Tracker.FormActMain.ActWebConnection.Update()

HTTP RFC2616:

Multiple message-header fields with the same field-name MAY be present in a message if and only if the entire field-value for that header field is defined as a comma-separated list [i.e., #(values)]. It MUST be possible to combine the multiple header fields into one "field-name: field-value" pair, without changing the semantics of the message, by appending each subsequent field-value to the first, each separated by a comma. The order in which header fields with the same field-name are received is therefore significant to the interpretation of the combined field value, and thus a proxy MUST NOT change the order of these field values when a message is forwarded