Oh, that's how you got in terminal. Sorry about my comment above. You're launch services are "confused" (the data base that associates files with what app handles them).
In the finder single click on one the .zip files to select it. Then either use the finder File menu, Get Info or just click command-I (eye). That will bring up the finder info window for that .zip file.
In that info window there will be a section titled "Open with:" with a popup menu below it. It probably says Terminal in it. If you click the popup menu there should be a list of apps that can handle .zip's (or what the system thinks can handle .zip's). Hopefully one of them will say Archive Utility. Select it and click the "Change All" button below the popup menu. Now all .zip's should use Archive Utility when you double click them. That handles .zips properly.
If you don't see Archive Utility in the popup menu the last entry in that menu is "Other...". Select that and you will see a window that lets you navigate through the file system. You need to navigate to /System/Library/CoreServices. Once in there you will find Archive Utility. Select it and again you can then click the "Change All" button.