what does 0x80040E14 mean in Sharepoint

Sorry about this question, i know it's very imprecise but i 've been trying for a long time to add a new item a row in a sharepoint site from a custom form but the server response the error 0x80040E14 what does it mean?. This site has a lot of subsites and was made a long time ago. I don't know much about Sharepoint (how it's structured, adding new sites inside another, etc) moreover i don't have the source for the site either. Does anybody give me a piece of advise about how to face this error?, I've been searching for validation and tried to change the settings but nothing.

Any suggestion will be welcomed Thanks.

Hope these links would be useful:

1. MS KB article
2. Microsoft Forum

MS KB article from first link says that the problem arose because content DBs were not updated correctly during upgrade. It is suggested to perform following to fix the problem: Windows SharePoint Services 3.0

1. Click Start, click Run, type cmd in the Open box, and then click OK.
2. At the command prompt, type the following lines, and then press ENTER after each line: cd /d %commonprogramfiles%\Microsoft Shared\web server extensions\12\BIN stsadm -o upgrade -forceupgrade
3. Type exit to exit Command Prompt.

For more details, please follow the link.