Agree with the previous post that clearing your temporary files and cookies will help. Suspect it helps because it reduced the amount of memory used for temp files. Also make sure that your pop-up blocker and ad blockers are off. Check any toolbars and make sure their pop-up blockers are off too.
I've occasionally had problems with surveys having tech problems and downloading problem if it has videos (I am on dial-up which slows that down alot). Usually there is a email address they give you just as you start the survey to contact them if you have problems. Jot that down just in case. It won't get you credit when you contact them, but it will give you satisfaction of letting them know of the problem you had. When/if you hear from them will also let you know that that site is worth trying again.
Other than that, just keep trying. I've had good luck with GUY2c (Give Us Your 2Cents), with minimal technical problems. When you do get to the final page, keep the page open until you see the credit booked to your FC account. I usually have another tab/window open to my account page and refresh it every couple of minutes to see if the survey has credited. It usually credits in less than 5 minutes. If I don't see the credit in 10 minutes, I just chalk it up to loss of communication and try another day.
You may only complete one survey from each survey site once in 24 hours. If you disqualify (DQ) for a survey, you can continue to try until you succeed (except for My Thought Counts -- they seem to have a daily limit on how many you can try, tho I don't know what it is -- and it applies to any and all GPT sites you visit)
My demographics are such that I usually complete 1 survey for each 10 I try for. Sometimes I'm lucky and complete one early; the other day it took 12 tries before I found a match. Keep trying and good luck!