SVN 436 gave me the same error , but reference the error as :
"Fatal error: Class 'rsgInstance' not found in ...\administrator\components\com_rsgallery2\includes\config.class.php on line 197"
I did not open the referenced class / source, to compare what was the difference.
The latest install [SVN 445] did not give me this error
.. but instead i experianced the same as in the thread :
http://rsgallery2.net/component/option,com_smf/Itemid,17/topic,8732.0oh well.. The developers are busy.. and they are movong forward <g>
Frank