TYPO3 Core

When trying to use the Linktool in the RTE i get:

Error in init.php: Path to TYPO3 main dir could not be resolved correctly.

This happens if the last 6 characters of this path, , (\$temp_path) is NOT "typo3/" for some reason.
You may have a strange server configuration. Or maybe you didn't set constant TYPO3_MOD_PATH in your module?

Array
(
[TYPO3_OS] =>
[PATH_thisScript] => /var/kunden/webs/version4/htdocs/typo3/sysext/rtehtmlarea/t3_popup.php
[php_sapi_name()] => apache
[TYPO3_MOD_PATH] => ext/rtehtmlarea/
[PATH_TRANSLATED] => /var/kunden/webs/version4/htdocs/typo3/sysext/rtehtmlarea/t3_popup.php
[SCRIPT_FILENAME] => /var/kunden/webs/version4/htdocs/typo3/sysext/rtehtmlarea/t3_popup.php
)

(issue imported from #M2116)