Excel and initializing series. Strange.

This seems like the strangest bug-- I fixed the problem I was having with my previous thread's issue by changing the way I select text into this code:

VB Code:

ActiveChart.SeriesCollection(1).XValues = Sheets("Snapshot SpdSht").Range("E2", "E50").Offset(0, DoubleCounter)
DoubleCounter=DoubleCounter+1

However, on the second iteration, the next part,

VB Code:

ActiveChart.SeriesCollection(1).Values = PVal()

fails, though it didnt before when I was reading a Values() array into the XValues.
I dont understand why it gives me a:
"Unable to set the values property of the series class." error message the second time through this loop.
Anyone have any ideas? it makes the graph right the first time.
Thanks

Edit:This does not only occur on the second loop. Sometimes, It can go through several loops before the error occurs. Strange.