If the source of your page is the same as you have posted I can see why you are having trouble viewing the captcha, in the code you posted the source for the captcha image looks like this:
{\field{\*\fldinst{HYPERLINK "view-source:http://127.0.0.1/UReg/WA_ValidationToolkit/WAVT_CaptchaSecurityImages.php?noisecolor=000000&bgcolor=ffffff&textcolor=000000&transparent=0&characters=5&width=200&height=40&font=WA_ValidationToolkit/Fonts/MACTYPE.TTF"}}{\fldrslt \cf2 \ul \ulc2 WA_ValidationToolkit/WAVT_CaptchaSecurityImages.php?noisecolor=000000&bgcolor=ffffff&textcolor=000000&transparent=0&characters=5&width=200&height=40&font=WA_ValidationToolkit/Fonts/MACTYPE.TTF}}
It should look like this:
"WA_ValidationToolkit/WAVT_CaptchaSecurityImages.php?noisecolor=000000&bgcolor=ffffff&textcolor=000000&transparent=0&characters=5&width=200&height=40&font=WA_ValidationToolkit/Fonts/MACTYPE.TTF"
So it seems that you may have something going on with your browser that is not allowing the images to be displayed properly. The same goes for the register button, it's source looks similar. Do you have another browser that you can use to view this page on your MAC? If the source for this image points to the correct location it should show the captcha without issue.
