You know I don't use the file manager to upload skins - I use either FTP as Salar suggested or actually installing via the skins/upload skin or admin/settings/ upload skin section, but if you are using the File Manager, part of the security settings include letting people upload only the type of files you want them too - specifically files that you know aren't going to be dangerous -

In the host settings/advanced/  you'll see a box called - File Upload Extensions and by default, only the following files are allowed for uploading. -

swf,jpg,jpeg,jpe,gif,bmp,png,doc,xls,ppt,pdf,txt,xml,xsl,css,zip

So, you can see - no html and no ascx file - so you need to change the permissions in the host settings to allow html and ascx files to upload but I think the reason it's not allowed is because of perceived security reasons.

In viewing this thread - I'm wondering if you are logging in as admin instead of host and by default the skin upload permissions don't seem to be allowed at admin level for you - which you can change in the host/settings section of your installation.

With so many downloads of dnn and this not being a common, prominent problem (like we have with some other things like the search functionality) I'm wondering if perhaps it's hopefully some confiiguration setting or maybe some more advice on what to tweak that will resolve this problem.

Hope this gives you some more ideas to work with.

Nina Meiers