Похоже, что эта работа сработала для меня. Мысли
Dim str As String = "this is exciting {video=""my/exciting/video.flv,my/refreshing/image.jpg""} this is refreshing"
Dim regFind As String = "(?'text'\{video=""(.*)\""})"
Dim matcher As Match = Regex.Match(str, regFind)
Dim Matched As String() = (matcher.Groups("text").Value).Split(",")
Dim video As String = Matched(0).Replace("{video=""", "")
Dim jpg As String = Matched(1).Replace("""}", "")
Response.Write(video)
Response.Write("<br />")
Response.Write(jpg)