Multiple kernel panics per day on MacBookPro4,1 2008 mostly in web surf mode
You log shows Google Chrome He as the problem maker.
Reinstalling the OS would not fix that since it is Chrome problem.
As for the problem solving, try following:

Uncheck the 'Enable hardware acceleration' checkbox to disable hardware acceleration for the Flash player in Chrome.

Follow this instructions to Resolve Kernel Panics.


Why did I recommend to test in Safe mode (in the comment above)

Rule out incompatible third-party kernel extensions, Startup Items,
and Login Items.
Start up in Safe Mode and use your Mac normally for a time to see if
the panic recurs. Third-party kernel extensions, Startup Items, and
Login Items are not loaded in Safe Mode. Note that running in Safe
Mode may prevent you from using third-party hardware that depends upon
associated third-party kernel extensions.
If the problem does not recur, then this implies a third-party kernel
extension, Startup Item, or Login Item may be the cause.
You can identify third-party kernel extensions by examining the panic log and then troubleshooting them by process of elimination. You
may also be able to identify the culprit by following steps 5 and 6
below.
To rule out corrupted or incompatible Startup Items or Login Items, follow the procedure specified in our &quot;Troubleshooting Startup
and Login Items&quot; FAQ to ascertain if these are causing kernel panics.