I have the same problem using IE10 with Win7/64. I can print everything from IE10 except BTyahoo email content; I can print all webpages, even the list of emails in the inbox, but cannot print the detail with an email due to a script error. The same issue also occurs in Windows Live Mail.
I have reset IE10, I have also run the IE repair program which resets a number of DLLs. Disabling all add-ons doesn't resolve.
I can print from emails in other webmail services - rather proves that it is a BTyahoo issue............
My conclusion is that it IS a BT Yahoo problem - call India and they are typically useless as most folks know.
How does one get BTyahoo to address this problem without going through useless hoops?