As it says, when viewing my project locally, everyhting is nice and smooth, and even after uploading the project’s default html and swf to my own webspace everything looks fine. However, when the guy who is taking care of the html side of things for a site we’re working on embeds the swf, you can clearly see aliasing. I initially thought that maybe it was using software rendering, but after switching off the hardware acceleration in the flash settings, the performance drops and I get odd triangles, so I am pretty sure that it is using the gpu, but just with the aliasing not working..

Also, my stage (or view)  is offset to the left..

Here’s the swf uploaded to my hosting:
http://www.margaretscratcher.co.uk/projects/CustomBike/index.html

and here it is embedded in the site:
http://www.aviciibikes.com/flash

Thanks in advance.

If things are offset to the left it sounds like you might have an issue with the size of your stage. What kind of stage scaling settings do you have?