There is no difference in the installer for Xeams Community and Enterprise Edition. It will run as if you have purchased the Enterprise Edition for the first 30 days. It will then get converted to Community Edition unless a license is purchased.
I try to gooogle this error,i found as below:
.xlsx HSSFWorkbook.xls XSSFWorkbook
Seems such error happen when the attached file is office2003 format .doc .xls