Not being allowed to use some terms in Add New Site in Wordpress

Question

The following words are reserved for use by WordPress functions and cannot be used as blog names: page, comments, blog, files, feed

This is the error message that I'm getting. I wanted to use /blog as a sub-site in the network. What I require is that my site has the following structure:

Home (only contains links to the other parts)
Part 1
Part 2
Blog

Would using permalinks solve my problem? I want all my blogs to appear in only the 'Blog' part of the site and nowhere else.

Another follow-up query is that, since I'm working on this site on my localhost, I'm using sub-folders. But when I eventually transfer the site on a web host, I want to use sub-domains. I'm mentioning this as I fear that any solution to the above problem can influence this.