[TYPO3-english] Upgrade Typo3 6.0.4 to 6.1.0

[Brian]

When I try and upgrade from 6.0.4 to 6.1.0 and I try and run the installer 
all I get is a blank page, no errors nothing.  I tried installing the .1.0 
intro package and it installs fine, so no problems with the server or MySQL 
versions or Apache or PHP settings.  There has to be something with all 
three of the web sites I have on versin 6.0.4.  All three site do the same 
thing.  What would cause the Installer not to load?  If I restore the old 
Typo3 folder and t3lib folder all three sites work great like nothing 
happened (also restore the index.php files from each site's root folder.  
All three site use system links and share the same typo3 and t3lib folders.

Any help would, of course, be of great help!

Thank you,

Brian