zipped folder error...

I had been trying to compress some folders on my flash drive to make room for other files, and I encountered some issues that may include one of the folders not copying correctly. And now when I try to open the zipped folder, I continuously get this message on my flash drive "Please insert the last disk of the Multi-Volume set and click OK to continue" and this message when I copy/paste the folder on my hard drive "Windows cannot open the folder. The Compressed (zipped) folder '(file-path)' is invalid." Can someone please tell me what's going on with it? I've tried opening it with Winzip, and I get the same issue... :4-dontkno