Hi PW,
I am sorry to see that you have not solved your problem. This is not an error that I have had or heard of until now. However, having said that, you really have not provided much detail beyond this error. Unfortunately, I have not worked with bugsXLA for several months now. In addition, I have since rebuilt my workstation and have still not re-installed either WinBUGS or Phils addin.
However, I wonder if you are not experiencing an issue that a few correspondents to this group have experienced when doing their first example 3.1. This may be of no consequence but this is some advice I gave to another user who had errors when executing Ex 3.1:
" I had opened the spreadsheet and started working on the example before I realized I needed the F2:F3 cells arranged as indicated in the text. (The spreadsheet - as you know - does not originally have the text filled in). So I exited BugsXLA and then filled in the cells in the Excel spreadsheet with TRT and * and then saved and closed Excel. Then I restarted Excel and the BugsXLA Add-in and the example worked without the error. Without doing further investigation, I assumed that once the Add-in starts running, it does recognize changes to the spreadsheet that was open when the Add-in first started."
So, if you load a spreadsheet and then start BugsXLA - but then you alter cells outside the "focus" or state of the spreadsheet you may get errors like the one you have received. Try exiting Excel. Reload the spreadsheet. First make the modifications you want to the spreadsheet - like adding cell headings or parameter/variable information. Save the spreadsheet with these modifications and then load BugsXLA and execute the steps required for your analysis.
If you can provide some additional detail - please do. As for Excel 32-bit running in a 64-bit OS - that is pretty much everybody's setup and it should not be causing you any difficulty.