According to the syntax of your current robocopy command, you're not specifying a file, and \\servers\installers\perfc will be read as a folder path. When no file is specified, robocopy automatically fills in *.* for the file name. This means that currently the robocopy command is looking for all files within the "\\servers\installers\perfc" folder.
For more information on the robocopy syntax you can check out
this article. I'm not entirely sure if robocopy will be able to deal with files without an extension.