3 days trying to figure this, please help

Ok so I install a new wordpress for a domain name, install my plugins but only activated wprobot, my theme etc, get wprobot set up, start it to post etc, then when I go and check my live url, I get this error on the right hand side.

Fatal error: Call to undefined function popular_posts() in /home/sonobby1/public_html/domainname.com/wp-content/themes/Reflux/sidebar.php on line 20

Ive tried everything I can think off, ive deleted the plugins, and tried again, ive deleted the whole wordpress installation, and installed again. Ive tried different themes, always the same error. One thing though, if I change the theme to the old basic wordpress theme, classic I think it was, then everything is fine.
But any better themes than I get this error, and its really doing my head in.
someone please help lol
Si

are you sure you're not missing a plugin that the theme requires?

Well it looks like your theme wants to use the wp popular posts plugin in its sidebar. Do you have that plugin installed?

Grizzy I noticed that so I found the plugin, installed it, and still the error.
dearac, thats a good question actually. I wanted to follow shezblogs blog guide, and he sugests around 10 different plugins, and they are different plugins to what I normally put on the theme.
I wonder if its a plugin im missing, umm
But I dont understand that, do you need plugins to make a theme to work, I not heard of that?

sonobby1 said:

Grizzy I noticed that so I found the plugin, installed it, and still the error.
dearac, thats a good question actually. I wanted to follow shezblogs blog guide, and he sugests around 10 different plugins, and they are different plugins to what I normally put on the theme.
I wonder if its a plugin im missing, umm
But I dont understand that, do you need plugins to make a theme to work, I not heard of that?

Click to expand...

well if you would like me to take a look just pm me. I fix those kind of errors for people all the time.

if you don't want me to look, pm me the link to get the theme and I'll install it on my local host to see if I have the same problems and find you a fix.

its sorted now thanks to dearac, thanks given
Si

i would suspect that maybe some files are virus infected.
i had this error some time back and i just deleted everything and reloaded the blog from scratch...that worked for me.
i figured it would take me 20mins to reload from scratch instead of busting my ass figuring it out....

junaidb said:

i would suspect that maybe some files are virus infected.
i had this error some time back and i just deleted everything and reloaded the blog from scratch...that worked for me.
i figured it would take me 20mins to reload from scratch instead of busting my ass figuring it out....

Click to expand...

Yes, because you can infect script files... (.html, .php, .cgi, and so on).

Don't say things you are unsure of, people read forums for information.