The next patch will include a fix that will show the error message directly in the "Manage app" page, instead of the "Updating..." message. Meanwhile you need to Abort the _MergeApplication command manually if it failed to remove the "Updating..." message.
Report with ID 148 is probably a report that you have deleted, but which was not deleted properly from the template database. We are not sure why some users are getting these problems, it happens with workspaces and other objects sometimes as well. If you can repeat this problem we would like to know how. See below for a manual solution that you can use for now.
Regarding how to fix it... Make sure that the report is actually removed. Query the database:
SELECT * FROM reportv3_report WHERE report_id = 148;
Empty result? Then run the following query:
SELECT * FROM template WHERE object_type LIKE '%ReportWriter%' AND object_id = 148;
What does the result look like? Is the "deleted" column set to 0 or 1? If set to 0, run the following query to delete the entire row:
DELETE FROM template WHERE object_type LIKE '%ReportWriter%' AND object_id = 148;