XML error Document is empty in one folder, but in other folder works fine

I'm translating a training module, (kind of a html presentation) and the information is extracted from a XML file with Javascript. I was provided with a link to the original module (Folder A), and a FTP account to upload the results (Folder B)

When I access to the XML file through the source folder, example: www.domain.com/folder_A/file.xml it works perfectly, displays all the tree with a structured content. However, If I download the file (through save link as) and upload the same file to another folder in the same domain i.e: www.domain.com/folder_B/file.xml when I try to open the xml file, I get this error:

This page contains the following errors:
error on line 1 at column 21: Document is empty
Below is a rendering of the page up to the first error.

Unfortunately, I don't have access to anything else in that hosting space or the source folder (folder A) I was just provided with FTP access to the folder B, in order to provide the final module translation (I noticed the website is hosted on HOSTGATOR.COM most likely Linux server). I do have another hosting spaces (Windows based) and I can open the XML perfectly and the module works fine.

I'm new working with XML, and since the module works perfectly on my hosting, I'm thinking that it might be a configuration or permission on the client hosting? However I'm not sure if that's possible, or if there's anything I can do to get it working. Any ideas?

The XML file looks kind of this:

   <?xml version="1.0"?>
    <data>
    <row type="Graphic" id="01">
        <LTitle><![CDATA[Module Introduction]]></LTitle>
        <sectionTitle><![CDATA[Welcome]]></sectionTitle>
    </row>
    <row type="Graphic" id="02">
        <LTitle><![CDATA[Overview]]></LTitle>
        <sectionTitle><![CDATA[Objectives "KPI" ]]></sectionTitle>
    </row>
    <row type="Graphic" id="03">
        <LTitle><![CDATA[Overview]]></LTitle>
        <sectionTitle><![CDATA[What is KPI - Performance ?]]></sectionTitle>
    </row> 
    </data>

Many more row tags with information, but basically the same structure.

Thanks for your help!