Welcome to Linux.
As a beginner you might want to consider telling us a little more info. Like what steps you took to download the .jpg file, and what you did to view the file where you got the error message (and what was the exact error message). Maybe even what email client you were using when trying to download the file.
As far as no sound in your browser, do you have "flash" installed?
I don't run Kubuntu, I run Debian sid and Fedora, but I did notice in my travels that regular Ubuntu will aid you with installing flash, while Kubuntu needs to have some manual intervention in order to get it working. In Debian, flash is called flashplugin-nonfree, I assume, in Kubuntu, it has a similar name, if not the same name. Try searching for flashplugin and see if it's installed.
Maybe a more experienced Kubuntu user could add a post with the exact filename.

On the contrary, I think there is good group here that respond within a reasonable amount of time. We don't send out e-mails as responses, but we do answer questions quickly in the thread when we are knowledgeable about the problem.
There are a few real guru's that read these threads on a daily basis. (I'm not a guru but I do read daily). If you read through the forum, you can see that there are many experts here.

As for the email responses, if you click the subscribe link at the bottom you will be emailed on the repsonses.

I was hoping thta somone else that uses Kubuntu could help you, but it is time for me to chime in.

I am having a simiilar issue when running KDE4 on another distro, my issue is caused when I have any media player running in the background, even when it is stopped I will not get broweser audio. This issue is caused because a specific application is tying up the audio device file.

Please check to make sure that you don't have xmms, audacous or amarok running when you try to get browser audio to try to single out the cause of the issue.

Please report your findings, I suspect that if that is not the case then we will need to see a lsof output to see what is locking the audio device file.