code igniter eval on library call

[eluser]newtonianb[/eluser]
I'm trying to run an eval on this string eval('$this->ci->lib_funcs->rmdir_recurse("C\\temp\\20110525")')

but it doesn't seem to be working. In my design I iterate through a stack of commands that I'm supposed to run which essentially "rollsback".

I have defined $this->ci =&get;_instance();
The lib_funcs has been loaded from the controller

Is there a way to accomplish this? I tried the command without the eval and it works.