Our friends on SalesLogix Developer originally posted this error and solution but I thought it was important enough to pass it on.  After upgrading a 6.2 db to 7.5 web and following the instructions for the upgrade the option to import leads returned an error "Import configuration not found for entity ILead."  The fix will be two steps, restore a SalesLogix 7.5 eval db, then using Virtual File System Explorer browse to the VFS\Configuration\Global folder and copy the files from the global folder to a temporary folder.  Now open the upgraded db and using VFS browse to the Global folder and add the following files ImportConfigurations.xml, MergeConfigurations.xml, and PotentialMatchConfiguration.xml.  While I have not tried restoring the manifest from the DVD which should work, this solution does seem to resolve the issue.