Perl FILEHANDLE Question?

I am trying to open a file in a perl program using the filehandles. I have the filepath/name stored in a string. I tried to open it like this: open(FILEHANDLE, $string) . It is not recognizing the string's value as a filepath. Does anyone know how to open a file whose filepath is stored in a string?
It is in a Unix environment. The file definitely exists because I can open the file via the filehandle by hard-coding the filename/path into the open method. I also made sure that the correct filename/path is stored in the string as well. What is happening is that it is saying the file that I am sending it doesn't exist.