Why does my HP48G program give this error??

[DM48]

Why does my program give me a \.S Error: Bad Argument Type ??

I have written a lot of these integration routines very similar to this on my HP48 but this one is not cooperating. It works when I put in numbers in place of variables. However, when I had the variables back in the program ceases to function.

I typed the below in by hand so I may have a few errors. I have attached a screenshot of the formula part as a reference.

Code:



\<< 48 58 12 6 \-> ID OD H OC

\<< ' \.S (0,H/2, \.S (-OC, \v/ (H/2-y^2) - OC, \v/((OD/2)^2 - x^2) - \v/((ID/2)^2-x^2),x),y)' \->NUM >>\ \>>

\( \large \int_{0}^{\frac{H}{2}}\int_{OC}^{\sqrt{\left ( \frac{H}{2} \right )^2-y^2}\: \: +OC}\sqrt{\left ( \frac {OD}{2} \right )^2- x^2} \: \: - \: \: \sqrt{\left ( \frac {ID}{2} \right )^2- x^2} \)