TopLeaf is a 32-bit application which will install and run properly on 64-bit Windows systems.

However, you also need a 32-bit Java run-time in order for some functions, such as PDF creation, to work.

After installing 32-bit Java, select the run-time in TopLeaf's "Preferences" dialog, on the "Folders" tab.

You can find 32-bit Java run-times here: