Hello Lydia,
Sorry it took a while to get back to you, you were generous with the info and deserved faster attention. To make matters worse, I have no answer for you yet, just some anecdotes.
I have faced a similar problem when the installation of OpenGL libraries or the graphics card drivers was not correct. In that case SUMA ran but nothing came up on the screen. If you suspect this is the case with you then you should try reinstalling OpenGL or Mesa libraries. If you have a graphics card with hardware support for OpenGL, try reinstalling its drivers first, recompile suma and see if the problem goes away. If the problem persists, try reinstalling Mesa then the drivers. There is some help on SUMA's webpage for installing OpenGL in case you have not looked at it yet.
I am considering putting a small OpenGL program in SUMA's source code distribution. The test program will be independent of SUMA so if it runs then SUMA is the likely culprit.
I will post a message here as soon as I have such a program added to the distribution.
cheers,
-ziad