I managed to locate the installation archive for FrontDoor 2.33.mL (DOS) and have made it available for download here. This is a self-extracting archive. Run it inside a DOS compatible session. You can also download the installation archive for FrontDoor 2.33.mL (DOS + OS/2) here.
OS/2
Corrective patch for FrontDoor/2 2.26.SW
A corrective patch for FrontDoor/2 2.26.SW has been released! This patch corrects a rather obscure problem with the OS/2 version of FrontDoor 2.26.SW. The problem only occurs for users that have purchased an OS/2-only license. To download the update patch for 2.26.SW (OS/2), click here.
FrontDoor 2.32.mL
FrontDoor 2.32.mL has been released! This release features a native 32-bit OS/2 version as well as a DOS version. Click here to download the update.
FrontDoor 2.26.SW
FrontDoor 2.26.SW (Shareware) has been released! This release features a native 32-bit OS/2 version as well as a DOS version. Click here to download the update.