On SharePoint 2010 you will run into the following error :
Log Name : Application Source : Microsoft-SharePoint Products-SharePoint Foundation Date : 9/27/2010 Event ID : 7043 Task Category : Web Controls Level : Error Keywords : User : MSS\SPFARM Computer : MOSSSERVER Description :
Load control template file /_controltemplates/TaxonomyPicker.ascx failed: Could not load type 'Microsoft.SharePoint.Portal.WebControls.TaxonomyPicker' from assembly 'Microsoft.SharePoint.Portal, Version=126.96.36.199, Culture=neutral, PublicKeyToken=71e9bce111e9429c'.
Here's how it looks it in the Application logs
The file drive:\Program Files\Common Files\Web Server Extensions\14\TEMPLATE\CONTROLTEMPLATES\TaxonomyPicker.ascx is badly formed and doesn't compile.
You can change the bad syntax of the file as follows
Sometimes, the error does not go away even after following the steps listed above. In such cases, the fix is to rename the 'TaxonomyPicker.ascx' to something like 'TaxonomyPicker.ascx_broken' so that we do not try to recompile it each time the AppPool is started. The user control is never used within SharePoint and therefore serves no real purpose.