When installing the template I received an error:
XML Parsing Error at 10:293. Error 23: EntityRef: expecting ';'

Anyone else getting this?

I had it too. I think there's something in the description of the site in the XML file, since it's referring to line 10. If you remove the description it will work, but I'm not sure how that will impact the terms and conditions. Perhaps admin can advise.

We will look at this as soon as possible. Thank you for your notes!

I'm getting this too. I get the XML parsing error, and in the Joomla Template Manager, it states:

The Parameter-File \templates\simplify_green\params.ini is Unwritable!

If I try to preview the template, it says "Restricted Access" in the upper-left corner of the browser. Even if I remove line 10 from the xml file, I still get the ini message.

Pretty much any other template works fine, just the estimete ones are giving me a hard time. I'm using Joomla! 1.5 - is that no good?

Using Joomla 1.5 and PHP5 (n Windows XP running XAMPP), I also get the XML parsing error, and in the Joomla Template Manager, it states:
The Parameter-File \templates\simplify_black\params.ini is Unwritable!
Also, if I preview the template, it says "Restricted Access" in the upper-left corner of the browser.

If I replace line 10 from the xml file with my own text, and provide an empty params.ini file, the ini message changes to
The Parameter-File \templates\simplify_black\params.ini is Writable!
But it still says "Restricted Access" in the upper-left corner of the browser.

I really hope someone can shed some light on this.
I'm going to try downloading a fresh copy of the template, but if that doesn't work I'll just have to move on.
The annoying thing is that 8 out of 10 'free' templates I've tried (this one from Estime, some from others, and 4 out of 4 from Sarkis) have failed with similar problems.

EDIT: Okay . . I see this template is shown as Joomla 1.0 compatible on this site, and I'm using J1.5. The site I downloaded from originally had this included amongst J1.5 templates. Oh the joys of OS . . .

Just downloaded the green simplify template today, great template by the way, but i too have the same error:

XML Parsing Error at 10:261. Error 4: not well-formed (invalid token)

right when i open the template manager. I have php 5 and joomla 1.5 if that helps.

I really have no clue what the heck it means but if it is fixable i would really like to use the template. But if not oh well i guess i will have to go elsewhere.