MuPad - Warning message on summation

Hi, I input the following code in MuPAD

s_i_i:=(K+a-p_i)/(1+sum(sum(sum(K+a(j,i)-p(j,l,n)-g(l), n=1..n(j,l)), l=1..L), j=1..T))

And got the following message:

Warning: The summation variable must not occur on the right side. [sum]

I did some Googling, and that message got me zero results. I can't be the first one to ever get it, right?

[Walter Roberson]

Try breaking it up into a series of statements. Either that will cure the problem or it will identify which of the summations is the problem.