I've tried downloading the extended trial of Creative suite without succes. Then I tried downloading the files directly - without luck - I keep getting the messages "The following disk images couldn't be opened" - invalid checksum.
I'm working with a MacBook Pro with OS X
Go to Finder > Type Disk Utility > Preferences and simply unchecking the box that says "Verify Checksums" . Close Disk Utility. Then Creative suite dmg should open fine and the program should install without any issues.
(You might want to re-check the verify checksums box after you've finished the installation though because it's there to help prevent the installation of corrupted .dmgs that could potentially harm your computer)