I have been using that addin, that provides additional astronomic functions for
CALC, for years. But with 3.0, that addin dos no longer work correctly, all
fields containing astroadd functions show message "#Name?".

There is a workaround to get the correct calculations: you only have to use
search / erplace for all equals signs, and the calculations will be done. but
after you saved and reloaded the document again, you will get the ugly messages
again.

Steps to reproduce: 
0. unzip "astroadd-1.5.3.zip" 
1. copy/paste "astroadd.dll" to your folder similar to
  <C:\Programme\OpenOffice.org\Basis 3.0\program\addin\astroadd.dll>
2. open demo document "astrodemo2.sdc" FROM THE ZIP
   expected: values are shown in the cells, charts with contents
   actual: Error messages, empty charts
3. Menu 'Edit -> Find & Replace', Search for "=", Replace with "=" in
   formulas for all sheets
   Calculations will be done.

No idea whether that is specific to "astroadd.dll" or a general addin problem.

NEW due to discussion on a.m. URL