Hi!
If the search page doesn`t go to the result page there must be something wrong in your
tpl_advanced_search_default.php file
or the
/include/modules/pages/advanced_search/header_php.php

you didn`t post your changes there, right?

and if your sure about the value of "dwarf" isn`t string than string is def. not the right variable type - but string should work as well (i think).

these are the possible variable types in php (as far as i know):
"array"
"double"
"integer"
"object"
"resource"
"string"
"unknown type"