How can I use a differnet hover image in a menu list?

Hello. I got this code from http://cooltext.com. But when I tried to edit it to use 2 different images it won't work. I can't get my hover image to display in the #menu li a:hover section of the style sheet. When I use the original image it works fine. But when I replace the original image with a different image in the code it goes blank when I hover my mouse over the button. Here is the code that works:

#menu {
      width: 200px;
      border-style: solid solid none solid;
      border-color: #0e69be;
      border-size: 1px;
      border-width: 1px;
      }

#menu ul{
      list-style:none;
      margin:0px;
      padding:0px;
      }
#menu li a {
      height: 32px;
        voice-family: "\"}\"";
        voice-family: inherit;
        height: 24px;
      text-decoration: none;
      font-weight:normal;
      }      
      
#menu li a:link, #menu li a:visited {
      color: #ffffff;
      display: block;
      background: url(images/menuImg1.jpg);
      background-repeat:no-repeat;
      padding: 8px 0 0 10px;
      }
      
#menu li a:hover {
      color: #ffffff;
      background: url(images/v5.jpg) 0 -32px;
      background-repeat:no-repeat;
      padding: 8px 0 0 10px;
      }
      
#menu li a:active {
      color: #ffffff;
      background: url(images/menuImg2.jpg) 0 -64px;
      background-repeat:no-repeat;
      padding: 8px 0 0 10px;
      }

But then when I change this section and hover my mouse over the button it goes blank. The new image doesn't display. I changed it from this:
#menu li a:hover {
      color: #ffffff;
      background: url(images/v5.jpg) 0 -32px;
      background-repeat:no-repeat;
      padding: 8px 0 0 10px;
      }

To this:
#menu li a:hover {
      color: #ffffff;
      background: url(images/menuImg1.jpg) 0 -32px;
      background-repeat:no-repeat;
      padding: 8px 0 0 10px;
      }

As you can see I only changed the filename to my new image. Any help will be appreciated.