Index: class.tx_rtehtmlarea_base.php
===================================================================
--- class.tx_rtehtmlarea_base.php	(revision 7283)
+++ class.tx_rtehtmlarea_base.php	(working copy)
@@ -440,7 +440,7 @@
 				if ($pathToSkin) {
 					$this->addStyleSheet(
 						'rtehtmlarea-plugin-' . $pluginId . '-skin',
-						($this->is_FE() ? t3lib_extMgm::siteRelPath($key) : t3lib_extMgm::extRelPath($key)) . $pathToSkin
+						($this->is_FE() ? t3lib_extMgm::siteRelPath($this-ID) : t3lib_extMgm::extRelPath($this->ID)) . $pathToSkin
 						);
 				}
 			}