I can confirm that my Windows 7 64bit machine gives me an error when importing an .PPTX file. I am using Office 2007.
The Error says
“Unable to import the PowerPoint presentation. Error: The message filter indicated that the application is busy. (Exception from HRESULT:0x8001010A (RPC_E_SERVERCALL_RETRYLATER)”
Another window from MS Powerpoint pops up and says
“Run-time error’ – 2147188160 (80048240)’:
Application (unknown member) : Invalid request. There is no active presentation.”
I was able to successfully import an older file format of Powerpoint, the regular PPT files.
So sraynor try saving as.. your presentation in the Powerpoint 97-2003 PPT format and NOT the PPTX one.