Have you ever thought why you get the error message "Exception has been thrown by the target of an invocation" when you try to create Public Folder Database in Exchange Server 2010.
Which is the component comes in picture when you create a Mailbox Database, Public Folder Database, Move Mailbox?
The answer is, Microsoft Exchange System Attendant is the component comes in picture when doing all the above things.
I was working with the client last week on Exchange 2010 migration from Exchange 2003. After installing Exchange 2010 SP1 without any issue, I found the it didn't created the Public Folder Database even after having outlook 2003 client in the environment.
I tried to move mailbox from 2003 to 2010 and it failed on 95%. I tried with another mailbox with 9 MB of size and it also failed on 95%.
I tried to create the Public Folder Database but got the below error message "Exception has been thrown by the target of an invocation".

I did lots of research and searched every where on the internet but didn't got anything related to it. I have to fix this issue as client had lots of outlook 2003 clients. I started reading about MS Exchange System Attendant service and it pointed me to Address List.
I checked in the client environment and found that they have one Address List say, ABC Address List.
I asked client about this address list and he said that address list contain nothing, its empty. I told him that due to the corruption of this Address List (ABC Address List) we are unable to create Public Folder Database. To get this fixed I will have to delete this address list.
Double checked and found that there is nothing in it and somebody has created it just like that long time ago. Deleted the address List from Adsiedit.msc and we were able to create Public Folder Database successfully. Moved the Mailboxes from 2003 to 2010 successfully.
Cheers,