Spy or Timeline Modules installation error!

On 7.3.1 when i try to install Spy or Timeline Module this is respectively the database message error:

SPY MODULE
Database error in Cupido.it - Innamorarsi in Rete

Query:

 INSERT INTO `sys_alerts` SET `unit` = '', `action` = 'add', `handler_id` = '52' 

Mysql error: Duplicate entry 'add-52' for key 'alert_handler'

Found error in the file '/home/cupido/public_html/cupido.it/modules/boonex/spy/classes/BxSpyDb.php' at line 249.
Called 'query' function with erroneous argument #0.


Debug backtrace:
.....

TIMELINE MODULE
Database error in Cupido.it - Innamorarsi in Rete

Query:

INSERT INTO `sys_alerts`(`unit`, `action`, `handler_id`) VALUES('', 'add', '56')

Mysql error: Duplicate entry 'add-56' for key 'alert_handler'

Found error in the file '/home/cupido/public_html/cupido.it/modules/boonex/wall/classes/BxWallDb.php' at line 37.
Called 'query' function with erroneous argument #0.


Debug backtrace:
....

I delete all cache before and after any installation but these errors are sistematic why this occur? How can fix it?

The problem is that 'unit' is empty.

It may happen when some module isn't correctly registered in the timeline. Also it maybe that some module wasn't correctly uninstalled.

I would suggest to remember if you've removed some of modules and double-check if it was completely removed.