Best thing to do: contact Maptech's helpdesk. If you do, be sure to know where "there" is ('vision.dll file is installed there'). And have a look at the properties of that file to see the details (company, description, version).

A few possibilities:
- it's the wrong vision.dll file (it's not part of Windows, so it must come from somewhere else).
- it's the correct file but the wrong version
- you've got another program on the machine using a vision.dll, which isn't overwritten by the install of Maptech
- error in Maptech's installation procedure
- dll needs to be registered

I don't know (and it's unlikely many people on this forum do), but Maptech surely will.

Hope this helps.