Checking for a file

I've not heard of a solution to this issue i'm having and have tried to cover my butt so I don't seem like a....well...you know what. Anyway, I want to check if a certain file exists in the same folder as my swf. I know in perl there is a

if(-e file.exe){
do this;
}

anyway..I know this isn't perl. I just was wondering if there is a command in flash that will return a true if the file exists or a false if it doesn't. Any help would be much appreciated.

Thanks