SSIS - excel import failing for "person A" but works when invoked by "person B" on server

SSIS 2012 using the 2010 Office connectivity code. Package setup to run under windows account on server. Works fine in VS on PC for myself. Fails on server. Works for another staff member when they launch package on server. I have sysadmin role on this SQL Server.

Created text import package test. Uploaded txt file to same location as excel file and it worked so do not have folder permissions issue.

I get following errors:

Data Flow Task:Error: "Excel Source" failed validation and returned validation 
status "VS_ISBROKEN".

and

Data Flow Task:Error: SSIS Error Code DTS_E_OLEDBERROR.  An OLE DB error has occurred. Error code: 0x80004005.

Are there additional permissions I need for this? Additional debugging suggestions...?

Thanks.