Excel 2010 :: Stopped Working When Building Charts?

I'm working on a macro that does the following:

1. Pull data from the internet
2. Perform calculations on the data
3. Graph the calculated values

- As I run the macro, Excel dies in step 3, where I graph the calculated values.
- It works about 5% of the time and gives me the "Excel has stopped working" error 95% of the time - I can't isolate any difference in the attempts
- I've located the area in the macro where it dies, but I can't identify the exact line since it seems to shift around in this area
- It works perfectly fine when I step through using F8
- I've attempted DoEvents and Application.Wait to debug. Application.Wait for 5 seconds allows the macro to work about 50% of the time and increases in efficiency the longer I wait
- Steps 1 and 2 work perfectly fine (I've used that code in many macros), so I'm pretty sure the issue is in the below code:

I'm running Windows 7, Office 2010

Code:
'Chart variables
Sheets("Summary").Select
Dim ChartRange As Range

[Code]....