I am having the same problem as the OP. I have manually edited the font-otr.lua file as per the patch below, and I deleted the font cache. But all to no avail. I still get:

!LuaTeX error: cannot find OpenType font file for reading ()
 ==> Fatal error occurred, no output PDF file produced!

Is there a solution to this?

Many thanks,
Talal

> On 8 Dec 2015, at 00:22, Philipp Gesang <phg@phi-gamma.net> wrote:
> 
> ···<date: 2015-12-06, Sunday>···<from: Hans Hagen>···
> 
>> On 12/6/2015 10:14 PM, Philipp Gesang wrote:
>>> ···<date: 2015-12-03, Thursday>···<from: Thangalin>···
>>> 
>>>> The problem persisted with Courier New, not only Source Sans Pro (SSP).
>>>> 
>>>> The font file for Source Sans Pro came directly from the Google's font service.
>>>> 
>>>> The SSP (on my machine) works fine in Inkscape.
>>>> 
>>>> The exact same font was also working before the ConTeXt upgrade.
>>> 
>>> Confirmed, it appears to work if you revert to the old loader in
>>> font-lib.mkvi.
>> 
>> i need a better example of what fails then as it works here
> 
> 
> The problem seems to be the “filename” field being written to the
> cache from the wrong source. Between the old and the new
> fontloader, you get the following picture in the “resources”
> record:
> 
>    +  ["filename"]="Everson_Mono_Bold.ttf",
>    -  ["filename"]="/tmp/here-be-fonts/Everson_Mono_Bold.ttf",
> 
> The attached patch fixes it for me.
> 
> Philipp
> 
> <font-otr.lua-fix-resources.filename.patch>___________________________________________________________________________________
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