Does Case-sensitivty matter ?

I have posted a subset of this before, so I apologize in advance, if this is construed as a repeat post:

I have 6 websites, under a domain (let’s call it domain.com). My domain has been in existence since 1997; hence, the “sandbox” issue should not be relevant here.

My 6 websites are constructed as sub-directories under my domain, i.e.:

http://www.domain.com/Site1/WebsiteName.htm
http://www.domain.com/Site2/WebsiteName.htm
.
.
.
http://www.domain.com/Site6/WebsiteName.htm

Note that my “Website Names” have letters capitalized at the beginning of a name within the page. For example, a top-level Page name called “Baseball Greatest Feats”, with my capitalization nomenclature would be named as:

BaseballGreatestFeats.htm

This turns out to be relevant. 5 of my 6 (sub-directory) websites under my domain are found fine in the GOOGLE SERP’s, whereas one of my sites is no where to be found, unless I type the URL directly into the GOOGLE search box. Further, if I type this effected URL all lowercase:

http://www.domain.com/Site6/websitename.htm

it is not found in Google. Whereas, if I type it in with the proper capitalization:

http://www.domain.com/Site6/WebsiteName.htm

it is found.

For my other 5 sites, if I do a similar test, and all sites are found, regardless of case.

I’m trying to ascertain why this 6th site doesn’t show up in the GOOGLE SERP’s for any of my keywords, and I’m baffled. However, I stumbled upon this “case sensitivity” issue noted above.

Could this have something to do with it not showing up in the SERP’s ????

BTW, the “problematic” site is a Casino Review site. Would the topic have anything to do with this perhaps ?