I had to create a report today that used information from two different data sources, the first was SQL Server, and the second was an Access database.  I needed to create an ODBC connection to the Access database first so that I could query the data in my report.  I am running Windows 7 64 bit, and from prevous experience I know that I should be creating a 32 bit ODBC connection and that Windows provides both a 64 bit and 32 bit ODBC manager.  I opened up my System32 folder and found the 32 bit ODBC executable, odbcad32.exe and launched it.  Much to my suprise, there was no Access driver listed in the manager.  I did some quick searching and came across this incredibly helpful article.  The article explains that the odbcad32.exe that exists in the System32 folder is in actuality the 64 bit ODBC manager, and that both the 32 bit and 64 bit ODBC managers exist in the 64 bit system directory, SysWOW64, with the 32 bit manager having the same name (odbcad32.exe) as the 64 bit in the 32 bit directory (is that enough bits yet?).  Once I found the proper manager, I was able to add my DSN and get the report running. 

On a side note: this issue came about after having solved another cool problem, which was using data from one dataset into another.  I’ll create another entry to describe that process and solution.

Hope this helps.  Happy Reporting!