I came across a strange problem with the article module in Dotnetnuke. When a user clicked on the edit button of an article, a 'Critical Error' would occur. If they clicked the edit button again, the edit page would load with no issues. The Site Log gave the full error message:

DotNetNuke.Services.Exceptions.PageLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at FreeTextBoxControls.Support.ResourceManager.LoadResource(Hashtable target, String language, String cacheKey) at FreeTextBoxControls.Support.ResourceManager.GetResources() at FreeTextBoxControls.Support.ResourceManager.GetString(String name) at FreeTextBoxControls.Support.Helper.PopulateDefaultDropDownList(ToolbarDropDownList toolbarDropDownList, FreeTextBox freeTextBox, ResourceManager resourceManager) at FreeTextBoxControls.FreeTextBox.OnPreRender(EventArgs e) at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at ...

This was caused by the language settings of the site being set to English New Zealand - the Free Text Box Control didn't have a corresponding xml language file hence the null reference exception when trying to load the resource. To fix this all I did was browse to [my site]\Providers\HtmlEditorProviders\Ftb3HtmlEditorProvider\ftb3\Languages, copy the en-US.xml file and rename it to en-NZ.xml.

Sweet!

Jimmy