Typo3 6.2 with the current version of the crawler from TER (3.5) gives this error when executed by the planner from cron:

PHP Fatal error:  require_once(): Failed opening required 'PATH_t3libclass.t3lib_page.php' (include_path='[...]') in [...]typo3conf/ext/crawler/class.tx_crawler_lib.php on line 30

Or if you open the crawler module in the Info-Module, you get only a blank screen and these errors in the log:

PHP Fatal error:  require_once(): Failed opening required 'PATH_t3libclass.t3lib_pagetree.php' (include_path='[...]') in [...]typo3conf/ext/crawler/modfunc1/class.tx_crawler_modfunc1.php on line 30, referer: http://[...]/typo3/mod.php?M=web_info&moduleToken=[...]

PHP Fatal error:  require_once(): Failed opening required 'PATH_t3libclass.t3lib_pagetree.php' (include_path='[...]') in [...]/typo3conf/ext/crawler/modfunc1/class.tx_crawler_modfunc1.php on line 30, referer: http://[...]/typo3/backend.php

I found a bug report for this exists in the crawler bugtracker for over a year now. And the current crawler version 3.6.2 also fixes the problem, but for some reason is not in the TER yet. So to solve the problem:

Download crawler version 3.6.2 and replace “/typo3conf/ext/crawler/” with the contents of this archive.

Hope this helps somebody solving the issue faster.