[Plugin: BuddyPress Activity Plus] IE8 issue

We use BP Activity Plus v 1.4.1 on the site with BP group documents v 0.4.3.3 (Buddy Press 1.6.1). In Chrome, Firefox and IE9 it looks good, but in IE8 the upload image button is displayed with bugs. Could you look on the IE8 issue and help with this IE8 issue ?

http://ww.wp.xz.cn/extend/plugins/buddypress-activity-plus/