Template Parse Error! what do i do?

[laneydotbiz]

After trying to add some Ad codes to my forum index template, using the calssic theme, i later tried to log in and discovered the error bellow

"It seems something has gone sour on the forum with the template system. This problem should only be temporary, so please come back later and try again. If you continue to see this message, please contact the administrator.
You can also try refreshing this page"
Pls what should i do as i will not want to loose all the data on my forum.

[Iz-no-gud]

I just found out that I have similar problem on my forum.
At first, the message was:
"Parse error: syntax error, unexpected '<', expecting T_VARIABLE or '$' in /home/trbusnip/public_html/forum/index.php on line 358"

Please, help!