It is related to MSSQL 2005 upgrade advisor.
This happens when you have install MSSQL 2005 and Windows tried to install 'Microsoft SQL Server 2005 Express Edition with Advanced Services Service Pack 4(KB2463332)' updates.
--> Click here.
'The error occurs because of a problem with BPACMD.EXE attempting to load BPAClient.dll. If you create a sub folder called 'BPAClient' inside the folder called 'BPA' (under 'C:\Program Files\Microsoft SQL Server\90\Setup Bootstrap\BPA') and copy BPAClient.dll (from the sibling bin directory) into this folder, then the upgrade advisor will work'
Do not ignore this error, this issue will slow down the startup process of your Windows tremendously, by as much as 2.5 times.
Follow the instruction to get it resolved.
This is definitely an issue with the update for (MSSQL 2005 Express Edition) and by default, there is shouldn't be any sub folder called 'BPAClient' inside BPA folder (under 'C:\Program Files\Microsoft SQL Server\90\Setup Bootstrap\BPA').