edit Ad link problemon iMasters WP AdServer

Hi,I think this is a good plugin: very simple.
There are therefore two problem:
1) when I want to edit the Ad url, it does not change
2) in the option window, when I put another format, this show an error, but it makes the work however

Can somebody tell me something about the first problem?

Thanks

http://ww.wp.xz.cn/extend/plugins/imasters-wp-adserver/