Can’t Insert Hyperlinks

Hello

I have searched for my problem but have not found anything quite like it so apologies if this is duplicated somewhere.

I am using the latest version of WordPress. I have installed a template that is unmodified, save for changing the top banner. When I’m in ‘visual’ mode, I’m unable to use the hyperlink function. The box appears but it’s blank and it says, in the bottom left of my screen, ‘done, but with errors on page’. I can’t write text into this box at all.
I am able to insert the links in the html mode but would really prefer not to have to do this if possible.
I’m using Internet Explorer – does anyone have any suggestions as to what I could do?

Many thanks
Sarah