Another one of those "meant to post this long ago, but completely forgot" issues.
When appending objects between one Korman blend to another, the objects that are imported carry over the PRP/page to which they were assigned in the other blend.
If the receiving blend doesn't have that particular page in the Age settings, when exporting, it rightly mentions "invalid page".
However, if you do switch the objects over to an existing page, the error still comes up when trying to export.
The current solution to this is to save, quit, then restart B4K.
Note that this seems to happen when changing objects over manually and with the "Move to Page" button.
Another one of those "meant to post this long ago, but completely forgot" issues.
When appending objects between one Korman blend to another, the objects that are imported carry over the PRP/page to which they were assigned in the other blend.
If the receiving blend doesn't have that particular page in the Age settings, when exporting, it rightly mentions "invalid page".
However, if you do switch the objects over to an existing page, the error still comes up when trying to export.
The current solution to this is to save, quit, then restart B4K.
Note that this seems to happen when changing objects over manually and with the "Move to Page" button.