A quick Google search turned up the following article on the SharePoint forum: http://social.technet.microsoft.com/Forums/en/sharepoint2010setup/thread/c894d98c-24ab-416c-aca9-ae57644deb5e
It turns out the issue is caused by bad code. Simply do a search for the file called TaxonomyPicker.ascx (C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\CONTROLTEMPLATES) and open it up in Notepad. Do a search for the characters “,” and replace it with a “,” (minus the quotation marks in both cases).
From this:
To this:
Thanks to Brian Lala, this can all be accomplished by creating and running the following script:
# Powershell script to implement the fix suggested in http://support.microsoft.com/kb/2481844
$TaxonomyPickerControl = "$env:CommonProgramFiles\Microsoft Shared\Web Server Extensions\14\TEMPLATE\CONTROLTEMPLATES\TaxonomyPicker.ascx"
Write-Host " - Making a backup copy of TaxonomyPicker.ascx..."
Copy-Item $TaxonomyPickerControl $TaxonomyPickerControl".bad"
$NewTaxonomyPickerControl = (Get-Content $TaxonomyPickerControl) -replace ',', ","
Write-Host " - Writing out new TaxonomyPicker.ascx..."
Set-Content -Path $TaxonomyPickerControl -Value $NewTaxonomyPickerControl
Write-Host " - Done! Press any key to exit..."
$null = $host.UI.RawUI.ReadKey("NoEcho,IncludeKeyDown")
Microsoft finally release a KB article on the issue which can be found here: http://support.microsoft.com/kb/2481844