Here's some installation and upgrade information from our Tech Support team. Symantec strongly recommends the following best practices:

1. Read the 5.1 Late Breaking News Technotes:

• Solaris http://entsupport.symantec.com/docs/334829
• Linux   http://entsupport.symantec.com/docs/335001
• AIX     http://entsupport.symantec.com/docs/334998

2. Use the Symantec Operation Readiness Tool for 5.1 installation and upgrade preparation:
https://sort.symantec.com

3. View the 5.1 instructional videos 
http://www.symantec.com/connect/sfha51

4. Read the 5.1  product Release Notes and installation documentation:
http://sfdoccentral.symantec.com