Were you trying the qDiscussionView as shareware or using it as part of licensed web parts? What is the version and build number (accessible from web part context menu About dialog)? This can help identify the issue as different installers for shareware and licensed install were provided.
You will have to change the web.config settings to bring more debug info for this problem. Please check the followings:
1. Locate the 12 hive under %Program Files%/Common Files/Microsoft Shared/web server extensions/12/TEMPLATE/Layouts/
2. Modify the web.config (make a backup first) and locate <system.web> tag and <compilation> tag underneath it (if not exists, please add) make sure you have <compilation debug="true"…> where "debug" attribute is set to "true".
3. Locate <customErrors> tag underneath <system.web> tag and set mode to "Off".
4. Locate <SharePoint> tag underneath <configuration> if exists and make sure CallStack attribute is set to "true".