SAP EP – Netweaver Portal

Symptom

Problem when accessing Office files using Internet Explorer on a SAP J2EE Netweaver KM system. The document opens fine the first time it’s accessed. However “The page can not be displayed” is displayed when the URL is visited again.
Clearing IE’s cache manually allows to open the document once again (once).
This happens for various Office items (Word, Excel, PowerPoint etc) once they were opened.

Reason and Prerequisites

The problem seems to occur only for long URLs (>= 255 characters), and is not related with the web server (i.e. reproducible with Microsoft Internet Information Services too).
The problem is described in the following Microsoft Knowledge Base articles:
http://support.microsoft.com/kb/300629: “Error message when you open an Excel workbook that has a URL that is longer than 255 characters: “ is locked for editing”"
http://support.microsoft.com/kb/416351: “You cannot open Office files in Internet Explorer”

Solution

This problem is client specific and can not be cleared by any change of SAP software.
Manual Workaround:
Clearing IE’s cache manually allows to open the document once again.