The file you are trying to open 'rwservlet' is in different format than specified by the file extension.

In the Windows environment:

1) Start -> Run -> Regedit (to open the registry)
2) Locate the following key path:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\ FEATURE_ZONE_ELEVATION\iexplore.exe

3) Change the value from '1' to '0'
4) Ensure that the following settings for the .xls & .html file types are unchecked:
a) Open Windows Explorer
b) Goto Tools/Folder Options/File Types tab
c) Select the Extension 'XLS' (or HTML) and Click on the Advanced button
d) Un-check the option 'Confirm Open after Download' & 'Browse in same window'
5) Select 'OK', then 'Apply'