File uploads to an application no longer working in Subject7

I have a Subject7 statement which uses the "File_Upload_Options" command to upload a file to a web application.   This used to work, but after a Subject7 update in August quit working.   I have several of these in various tests for different applications which have stopped working, so it not limited to one application or test.

The error message I get is:

 
PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

I have verified that:

• The locator is still finding the Choose File area (I did this by using the locator in a verify_element statement.
• The file is available and downloadable in the "File Uploads" area of Subject7.
• I can manually upload a file to the application with no issues.

Any ides what is causing this?