Excel report generation errors

[AJL]

I have an application where I read data from an Access Database and generate multiple excel workbooks.  Each workbook contains five worksheets (one table and four graphs).  This application has been running for several months but now I am getting two different error messages.  One, the most common, is Error -2147352571, a type mismatch in Excel.Create_Workbook.  The other is Error -2146777998, at arg 1 of property node in Excel_open.vi.  Arg 1 is the display Alerts Property on this particular prop node.  I believe there may be a timing issue because I can create individual workbooks fine but when I try to create several back to back I get the errors.  I tried slowing down the loop all this is running in but the errors still come in. 

Any ideas?

BTW- I'm using LV 9.0.1 on a Core 2 Duo with Excel 2007

Thanks,

AJL

[muks]

Have you seen this discussion?

[AJL]

When I looked at the processes running, at the suggestion of the thread in MUKS reply, I noticed EXCEL.EXE and GRAPH.EXE stayed running.  I am using the NI Report Generation Toolkit (2009) to do all my report functions and I do not create any reference on my own.  Has anyone seen any "bugs" with this toolkit where references are not being properly handled?

Thanks,

AJL