Inventory Policies and Tasks fail to load: A critical error has occurred on this page. Check the Altiris Logs for more details.
This is a known issue relating to the Software Library.
The error stems from the File scan rules that are part of the policy. Part of loading the page involves enumerating the folder exclusions, including the Software Library location. While the cause is unknown, the library location gets into a state where the SQL throws the errors shown in the log when the problem occurs.
To resolve the issue, go to Settings > All Settings > Software > Software Catalog and Library Settings > select Software Library Configuration. Click on Validate, and then click Save changes. This should resolve the issue.
Inventory Solution 7.5, possibly 7.1 as well