Load control template file /_controltemplates/TaxonomyPicker.ascx failed: Could not Event viewer Error : load type ‘Microsoft.SharePoint.Portal.WebControls.TaxonomyPicker’ from assembly ‘Microsoft.SharePoint.Portal, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c’.

This is not causing any issues except for a wrong ULS log message a single time in a web application process life time, the exception is caught and that template file is skipped. This message should be treated as log noise and can be ignored.
To change this behavior:

Navigate to /14/TEMPLATE/ControlTemplates/TaxonomyPicker.ascx user control
Open the user control in a text editor and locate the first line
Find the character string , [in First line itself] and replace with a comma ‘,’ (without quotes).
Save the user control.

For more information click here