fundraising plugin on multisite wp with catalog structure WRONG CATALOG for pledge url

My fundraisers page is conigured in plugin settings to http://fondfrukt.ru/"fundraisers", but because of this site being main of my multisite structure, this link transforms to http://fondfrukt.ru/blog/fundraisers. It shows rather correct (some troubles with styles, but i haven't looked out for css problems yet). But when I push the "Fund it" button, the browser goes to http://fondfrukt.ru/blog/fundraisers/tower/pledge/ instead of http://fondfrukt.ru/fundraisers/tower/pledge/ as set in the settings.
Need to correct some string in plugin code to make this plugin work with WP MU with catalog structure.

Hope for your help!