A likely explanation is that you have two separate versions of LEAP installed (for example, they could be installed in different directories). When you work on a model in LEAP and click Save, LEAP stores your files within your Documents\LEAP Areas directory. This is the default, unless you have changed the location of this directory through the Basic Params window. The next time you open LEAP, it will attempt to load the last model you were working on. So, if you save a LEAP area using a recent version of LEAP, and then start an older version of LEAP (or try to load the saved area into an older version of LEAP), you may see the message you point out.

To avoid this, I suggest making sure that you have only one version of LEAP installed (i.e. the latest 32-bit version available here). If you're not sure how many you have installed, the simplest way to proceed is to uninstall all versions using Add or Remore Programs in Windows, and then install the latest version using the setup.exe file. Your Documents\LEAP Areas directory will remain intact, as will all of your models.

Let me know how this works,

Taylor