I made a little site for a friend:

lifeisforlivingwell.co.uk

She then wanted another - and the hosting package she had allowed another database and add-on domains, so,

tian-garden-acupuncture.co.uk was made, it points to an ss installation in a folder situated like so:

public_html/tian-garden-acupuncture.co.uk/ on lifeisforlivingwell.co.uk

and everything seemed to be working fine, without any .htaccess fun (ie, rewritebase is just /).

But I just tried to install the newsletter module, and while it worked fine on my local copy, it breaks the live site, with an error that says

"Website Error
There has been an error

The website server has not been able to respond to your request."

This happens even without trying dev/build and happens regardless of which module I try (have tried blog, userforms and newsletter. I can't actually try to build as it returns the same error. It just happens as soon as I upload the module folders to the root (which, by the way, it took me overly long to find particularly clear and detailed instructions for installing modules).

I'm thinking it's a .htaccess issue but am not quite sure what I should be doing to it as I'm just learning! Can anyone help?!

Just for information's sake - I had similar problems with another site - seems that if you try to install both the newsletter and userforms modules at the same time ie upload both folders at once (as they are both required, you'd think this'd work, no?) then it breaks. I did newsletter first and then userforms and seems to be happy. To save someone else the headscratching, it may be worth stating somewhere that modules must be installed individually?