Hello Cindy,
Thank you for contacting Cisco support community center. I'm sorry that you are having the inconvenience mentioned.
Are you trying to upgrade using HTTP or TFTP?
Which web browser are you using for the upgrade? Have you tried a different browser?
If a different browser didn't work, I would suggest to disable the single point setup and test if the upgrade is successful.Just in case, I've included below a guide with the steps needed to upgrade the firmware.
http://sbkb.cisco.com/CiscoSB/ukp.aspx?vw=1&docid=53283703d9ce41f8889737b8605e0ce1_Firmware_Upgrade_on_WAP121_Access_Point.xml&pid=4&fcid=&fpid=&slnid=5
If you are still having issues with the upgrade, could you please attach a screenshot of the error received?
If I can be of any further assistance, please, let me know.