1. At which point you get this error message? Which part of the
application issues it? Make sure that "application/vnd-ms-excel" is in the
list of cached MIME types in Webbrowser > File caching, and "Allow file
caching" is set to "Allow only for MIME types specified below".
2. In ZPE you can save it directly to disk. There is no need to "download"
it, as this can be confusing to the end user - to download something from
a Windows program. If you save it directly to disk, then you can launch it
automatically in Excel with Javascript command
external.ShellExecute(external.HWND, 'open', excelFilePath, '', '',
SW_SHOWNORMAL);