I was having problems getting Macromedia Flash to upgrade on my Mac OS X (Macromedia has not spent the time on this as they have for the Windows world) and it would not upgrade. I really wanted/needed Flash 6 for some very valid reasons
and I was finding many enterprise sites using only Flash 6 (not that they were using Flash 6 functionality) accessible files. I spent a couple weeks with no luck. I found the hint to manually delete the flash files from the library directories prior to running the upgrade. Magically I have Flash 6 now running wonderfully on OS X.