[TYPO3-english] value "" for "M" was not found as a module

[Tomasz Krawczyk]

Hello,

I have such message when I click "Save & Close" icon in the List module. 
Records are saved but this message remains on the right panel.

I saw similar messages on the google but it looks that such bugs were 
fixed in the past. Now I use TYPO3 v 4.5.2.

I don't know what causes that message. My PHP error_log is empty and I 
don't see any errors or warnings in my TYPO3 log.

Can anyone suggest what can it cause? What should I look for?

regards
Tomek