Hi this error also happened to on 2 of my client machines last thuesday morning when the automatic update suggested to update from Current Client Version 8.1 (Build 930) to -> New Client found Version 10.0 (Build 1166).
My server version is = 2X ApplicationServer & LoadBalancer Console version 5.1 (build 313)
After the update the clients got this error = Code [01/00000001], The specified remote 2X Connection could not be found., Verify that you have typed the correct computer name or IP adress, and the try to connect again.
To make it work again I had to uninstall 2X boot the machine and the run CCleaner http://www.piriform.com/ccleaner/download
to remove the regkeys that the 2X uninstaller did not remove. Boot again and then install 2X version 8.1 again + disable the automatic update. On the second machine I had a dialog box saying that Microsoft RDP control was not found even though it worked fine before, when I did the install the 2X failed to start, but I fixed it via Microsoft KB 951607 http://support.microsoft.com/kb/951607
@dlb did you find any solution?