I have experienced a new error when adding a new document type. Any ideas what it might be?

Thanks,

Janusz


Server Error in '/' Application.
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Key cannot be null. Parameter name: key
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentNullException: Key cannot be null. Parameter name: key

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[ArgumentNullException: Key cannot be null.
Parameter name: key]
System.Collections.Hashtable.get_Item(Object key) +340
System.Data.DataColumnCollection.get_Item(String name) +16
System.Data.DataRow.set_Item(String columnName, Object value) +55
Kentico.CMS.Form.BasicForm.SetDataRow(String columnName, Object value) +430
Kentico.CMS.Form.BasicForm.SaveData(String redirectUrlAfterSave) +6650
Kentico.CMS.Form.BasicForm.SaveDataClick(Object sender, EventArgs e) +13
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +57
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +18
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33
System.Web.UI.Page.ProcessRequestMain() +1292