Why does this fail on lines 5-7?

Code:
Dim seriesArray() As Series
ReDim seriesArray(arrayLength)
Dim tempSeries As Series
 For x = 0 To (lstLine.ListCount - 1)
        tempSeries.Name = CStr(lstLine.List(x).Text)
tempSeries.XValues = "=SOILSYM_MONTH!R" & findBeginRow(lstLine.List(x), firstMonth) & "C1:R" & findEndRow(lstLine.List(x), lastMonth) & "C1"
        tempSeries.Values = "=SOILSYM_MONTH!R" & findBeginRow(lstLine.List(x), firstMonth) & "C4:R" & findEndRow(lstLine.List(x), lastMonth) & "C4"
        seriesArray(x) = tempSeries
    Next x
it is failing on tempSeries.name = CStr(lstLine.list(x).text) and the following 3 lines of code... What I'm trying to do is create individual series and eventually add them all to a chart.seriescollection.... am I going about this all wrong?