Having dowloaded the code for Excel 2003 VBA Programmer's Reference I have loaded the file bulletproof.xls.

The normal Excel interface looks as if it has failed to load anything, but after loading the VBE, the project explorer shows the 3 worksheets and and on entering the password their underlying code, as well as that of the two modules.

If I use the immediate window, "? worksheets.count" gives an error 1004,
and "?activeworkbook.name" gives an error 91.

If I create a new workbook and copy the code into identical worksheets and modules everything is OK and the above commands work perfectly.

What are the settings in the original workbook that cause Excel to produce these errors?