No plugin installs at all

I have a website with a shared hosting company. They supply wordpress to all their customers. I tried installing some plugins that add twitter and facebook to the blog. But none worked.
They did give a message that they were ‘installing’ and I did have the option to ‘activate them’ (which I did), but they didn’t appear – not on old blog postings, and not on new ones either.
I’m thinking my company must be at fault, but they tell me they simply will not help. They do not support third party software, which I can understand, but if its not my fault, they should have looked into it.
Is there anything I can try?