Compile error in hidden module: security
 

Hi,

I've installed an addin, then installed an upgrade to that addin.

Problem is that since the upgrade, when I try to use the addin or when I
activate it using the Tools- Addins menu, I get the following error
messages (in that order):

1. Compile Error in hidden module: security
2. Can't find project or library
3. Password (Here i'm asked to fill in a password. I think here I have to
put the VBA project password which I don't know)

Notes:
1. Addin is password protected so I can't see it's code.
2. I don't know the password, and by far I don't have any way of getting it.
3. It works fine if I just install the upgraded addin in a computer which
doesn't have the first (old) version. I mean problem occurs only if I
UPGRADE from an earlier version, but does not occur if I install the new
version in a computer without the old version.
4. Uninstalling, then reinstalling Office did not solve the problem.
5. I'm using Office2000 Proffessional.
6. I've tried deleting all the .xla files in the computer, and all the
directories which are created by the addin installation, but it didn't help.
7. I've tried manually choosing the correct new version .xla file using the
Tools - Addins - Browse menu, but that didn't help either.
8. I was told that in order to solve that I must run some registry change
command (I don't remember the exact command) but that didn't help either.

Kind Regards,
Amir.