I was trying to install TMS Component v6.0 into my Delphi 7 (yes, it’s very old), everything seems working fine. I can see the new components installed, i can drag it to my form. Run it perfectly. Then i saved the form, project , re-open them , an error message showing up: “Error Reading Form” – Class TAdvPage not found.

Delphi7 Class Not Found TMS Component

What happened here? i could see it in my design pallet, i searched google and they suggest that the design package was not installed ? I could design it, so it must be installed. I have been struggling this for many days. It turned out that i was wrong, i need to install the design package (tmsded7.dpk)

borland delphi design package (1)

After i install the design package, it worked perfectly.

In the TMS Components, there are many packages, the package with …DE.. is for design purpose, you need to install it as well.