I use Sony AVC with the internet 1280 x 720 25p template to render 50p EX-1 MXF files, changing 25p for 50p. It worked impeccably until recently: Only 25p will render. Changing to 50p generates an error:

"an error occurred while creating the media file. The reason for the error could not be determined"

This occurs on different computers, also with mxf files that were used for 50p renders before.

Any relation to Vegas 10e or recent Windows 7 updates?