The line dsin=sum(terms) isn't summing anything, since terms isn't a vector. You can either make it a vector, or initialise dsin and change the line to dsin=dsin+terms.
Also your Taylor series for sine was using the wrong indices, you only need odd numbers for n, so increment +2 instead of +1 (making sure that the +/- signs are still in the right places).
degree=input('Enter the value of x in degrees to compute sin(x): ');
while error >=(10^-5)
newTerms = ((-1)^(n/2))*(((x^(n+1)))/factorial(n+1))