1. Try to republish your site again in FrontPage
2. If the error displays again, click OK
3. The above should allow FrontPage to bypass the error and continue publishing. If not, then proceed with steps below:

A. Local Copy of Website

Ensure you have a local backup copy of your website (Once the files are deleted from your Netfirms account, they cannot be recovered).

B. Reset FrontPage extensions

1. Login to the Netfirms Members Control Panel
2. Click Hosting
3. Choose Advanced
4. Click FrontPage Extensions
5. Click the Reset button

C. Remove any residual corrupted files (vti files):

To delete your web files from the remote site with Filezilla:

1. Login to your FTP account (input your domain name as the host site/server, input your userid and then your password as indicated in your Welcome Email )3. From the Remote Site, highlight the filename you wish to delete by right-clicking on the filename once and then choose Delete from the pull-down menu
2. Repeat above steps as necessary

To delete your web files from the remote site with WS FTP:

1. Login to your FTP account (input your domain name as the host site/server, input your userid and then your password as indicated in your Welcome Email )
2. Once a connection has been established a list of files on the remote server will be displayed on the right half of the WS FTP display. This section is indicated by Remote Site
3. From the Remote Site, highlight the file you wish to delete by clicking on the filename once
4. Click the Delete button displayed in the right side
5. Repeat above steps as necessary

To delete your web files from the remote site with MS FrontPage:

1. From your FrontPage program, click File -> Open Web
2. Enter: < http://membername.netfirms.com> (where membername is the Member Name assigned to your Netfirms hosting account)
3. Enter your userid and password (This will connect you directly to your ftp account on our server)
4. Select the file in your Frontpage software and click Delete

D. Republish Your Website
1. Republish your site in FrontPage

NOTE:
The server side extensions reads the vti files and thus displaying the interactive components of the website such as the themes and hover buttons etc..

If you were to hand code your site, you would need to use such programming language as css to display themes or javascript for the hover buttons. Frontpage does this programming for you and the software language created is vti files . If you were to open a vti file you would see software created programming .

If the vti files corrupt while publishing , rewriting , or do not fully publish ( if the server times out ) they cannot connect to the server side extensions and display your site correctly , thus it will appear that the FP server extensions were not installed.

When you re-publish changed pages to your site, it is better to select changed pages, because then there is less of a chance of the current extensions on the server corrupting .

You can read more at: http://office.microsoft.com/en-us/FX010858021033.aspx