Blob error in WebGL

Hey everyone, I'm a 3D artist trying desperately to debug a WebGL build of a virtual tour, getting this error in my WebGL build on Firefox. I get a slightly different but similar result on Google Chrome.

In case you're wondering, TriumphantArtists.com is a domain I own (one of about ten) where I'm temporarily testing a WebGL build in one of the subfolders. So that's why it appears in the code:

Error loading this URL: Could not load the source for blob:http://www.triumphantartists.com/4c70ac6b-bb34-4f86-92a4-d8da78d0c427. [Exception... "Failed to open input source 'file:////www.triumphantartists.com/4c70ac6b-bb34-4f86-92a4-d8da78d0c427'" nsresult: "0x80520001 (NS_ERROR_FILE_UNRECOGNIZED_PATH)" location: "JS frame :: resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/DevToolsUtils.js :: mainThreadFetch :: line 500" data: yes] Stack: mainThreadFetch@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/DevToolsUtils.js:500:5 SourceActor<._getSourceText/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/server/actors/source.js:380:29 Handler.prototype.process@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:937:23 this.PromiseWalker.walkerLoop@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:816:7 this.PromiseWalker.scheduleWalkerLoop/<@resource://gre/modules/Promise.jsm -> resource://gre/modules/Promise-backend.js:750:11 Line: 500, column: 0

Has anyone encountered this error before and does anyone have any idea what is causing it?

Thanks.