Inspiron 5100 A06 BIOS

I have a number of Inspiron 5100 laptops at a community college in Kansas that currently have the Phoenix A06 BIOS Rev. installed.  I would like to know the proper path to upgrading the BIOS to the current A32 revision. When I ran the install for the A32 it failed.   Also, please advise on locations of the appropriate downloads.