Here is how to correctly upload a site template (.stp) into MOSS.
1. If the site template file is an exe, download it and unzip the file on your computer.
2. Log on to SharePoint (as an administrator) to the site collection where you want to upload this template. Make sure to browse to the top level site of the site collection.
3. Go to Site Actions --> Site Settings -->Manage All Site Settings --> look for the Galleries section and select Site templates.
4. Select Upload --> 'Upload document' or 'Upload multiple documents' depending on how many site templates you wish to upload.
5. Browse to the
6. The site template should now be ready to go.
Applying the new Site Template to new sites:
1. Log on to SharePoint (as an administrator) to the site under which you want to create a site based on the newly uploaded template.
2. Go to Site Actions --> Site Settings --> Manage all Site Settings --> 'Create' or 'Create Site'.
3. Enter a title, URL and pick the new template from the 'Select a template' section.
4. Click Create. A site based on the new template should now be created.