Notice: Array to string conversion in C:\WEB\drupal7\modules\system\system.module on line 2785

This happens if you go to the admin/reports/status.
The problem consists when you install both modules:
1) The SimpleAds
2) Views slideshow cycle (from the views slideshow module)

Both of the modules uses incorrect hook_requirements implementation in the Return value

"An associative array where the keys are arbitrary but must be unique (it is suggested to use the module short name as a prefix) and the values are ..."

... but both of the modules uses 'jquery.cycle' as the key of the returning requirements array! The returned arrays are merged and the 'title' element in the array becomes an array - and this is what the warning is about.