upgrade for phpbb2.0.20 and ADR problem!

[Skywalker]

after installing hte upgrade to 2.0.20 i got this error in the acp:

[code]  Warning]

this is the code causing this:
[code]  // Work around for "current" Apache 2 + PHP module which seems to not// cope with private cache control settingif (!empty($HTTP_SERVER_VARS['SERVER_SOFTWARE']) && strstr($HTTP_SERVER_VARS['SERVER_SOFTWARE'], 'Apache/2')){     header ('Cache-Control]

in the page_header this code also gives the same error with adr

someone knows a fix for this?

right now i use a different header for adr where that code is deleted from.

but in the acp i cannot do that....