Believe me, we do get a lot of problems with this on the forums. Often people don't understand what causes the problem, and most importantly how to fix it. The purpose of this thread is to be linked to whenever a person has a trouble installing Messenger Plus! with this error.

What is the error?
This thread applies to you if you have an error similar to this:



The above image is just an example I found on a Google image search, but the same principal applies. The error is not caused by Messenger Plus! but an error on your computer.

What causes the error?
Many things can cause an application not be to valid. However most likely the installer for Messenger Plus! has become corrupt in some way. How? Well the way an Internet browser works (e.g. Internet Explorer) is by instead of downloading the same web page again and again, it uses something called a 'cache' to store web pages temporarily, and all images etc around it. Each time you attempt to view that web page, it simply loads the stuff you visited in the past.

When you downloaded Messenger Plus! it became corrupt due to an error your computer made when downloading it, and instead of downloading a new version of the file each time, your browser just keeps on loading the same corrupt file from your browser's cache.

How to fix it
There are two simple ways to fix the error. Both are explained below:

• Downloading from a mirror: This means downloading the file from a different location. Messenger Plus! is stored safely from thousands of locations around the Internet. However there is one main and trusted mirror of the product, it is hosted on Simtel.net:
  - http://www.simtel.net/product.download.mirrors.php?id=96937
  
  
• The other way to fix it is clearing your Internet Browser's cache. Below is an example of the mostly highly used browser, Internet Explorer:
  
  Right click the icon on your desktop and select properties. Within the first tab, depending on what version of Internet Explorer you are using (I am using version 7) click 'Delete ...'. A child window will pop up asking you what to delete. If you are using version 6 of the browser just go ahead and ignore 'offline content' and wait for what could be a few minutes (mostly likely a lot less) for the files to clear. Otherwise if you are using version 7 just select delete temporary Internet files and wait:
  
  
  
  You can now download Messenger Plus! like you normally would:
  - http://www.msgpluslive.net/download/