TimeTrex Time and Attendance

i try to see the error and this error appear:
DEBUG [137]: [Function](): Production: 1
DEBUG [92]: TTDate::setTimeZone(): Setting TimeZone: PST8PDT

why i'm getting this error:

"Warning: mail() [function.mail]: SMTP server response: 550 5.7.1 Unable to relay for root@localhost in C:\Inetpub\wwwroot\TimeTrex\classes\modules\core\Debug.class.php on line 166"

i'm confused here where when i want to download timetrax v1.4.0, it will be directly download timetrax standard edition v1.3.1. is it correct??

for your information i have already download and install timetrax v1.4.0 and it seem that the my php v5.2.0 still unsupported...

i have install php v5.2.0 in my computer and need to install timetrex system, unfortunetly, my new php version is unsupported. I need some help to solve this problem.