Error: Output routine didn't use all of box255

I get this error message for my footer:

begin{textblock*}{0.9cm}(3.5cm,9.25cm)
raggedleft
{usebeamercolor[fg]{title in head/foot}usebeamerfont{title in head/foot} 
hspace*{10cm}{textbf{IEB}hspace*{0.5cm}insertframenumber}}
end{textblock*}

%hspace*{0.5cm}

begin{textblock*}{3cm}(2cm,9.25cm)
{usebeamercolor[fg]{author in head/foot}
usebeamerfont{author in head/foot}insertshortauthor}
end{textblock*}

%Nombre del curso
begin{textblock*}{7cm}(-0.9cm,9.25cm) 
raggedleft
{usebeamercolor[fg]{title in head/foot}
usebeamerfont{title in head/foot}  titulo insertshorttitle}
end{textblock*}