Three possible solutions:

First Possible Solution:

- In IE7 there is a setting under Security.

Click on Tools>Internet Options, then select Security>Local intranets.

 Click on the 'Sites' button.

 Untick Automatically detect network paths and tick include all network paths( UNC's) 

 Windows7 - You must add the mapped Ostendo network drive (eg: O:\) to the Trusted Sites in the Local Intranet zone. 

Second Possible Solution:

 - You can get a resolution from the following links

http://support.microsoft.com/kb/896358

http://support.microsoft.com/kb/896054/en-us

Create the following script through notepad and run on each client PC.

Modify the script below to point to your server where the script says 'smserver' and your Ostendo mapped drive where the scripts says 'O'.  Save the modified file with the .reg ending, and double click to run it (must have Administrator rights, and run for each user accessing the server).

The script is:

REGEDIT4

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions]

"UrlAllowList"="\\\\smserver\ostendo;file://\\\\smserver\ostendo;O:\;file://\\O:\"

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions]

"MaxAllowedZone"=dword:00000002

Third Possible Solution:

Copy the CHM help files from the Ostendo folder up to each client machines "My Documents' folder. Ensure these files are placed at the root level of this folder.