The most common install problems are usually database issues.
Oracle SQL errors usually appear as:
Note: The following messages are expected (and can be ignored) for upgrades or reinstalls:
ORA-01921: role name XXXX conflicts with another user or role name
ORA-01920: user name XXXXX conflicts with another user or role name
RUNSQL (table creation errors) appear as:
RUNSQL ended in error. Return code is -1652.
If you have database issues, please refer to 3.5.1 Database.
It is safe to re-run the install after you have resolved the issues that caused problems.