Express.js throws Error: ENOENT on linux server

So, I have been working on an upload script (code is below) that I have working on my windows machine, but on my Linux server it seems to fail with

Error: ENOENT, open 'uploads/da5ab67b48ea2deecd25127186017083'

I understand that the error is saying there is no path/file, but I do check to for file existence before I attempt the file rename.

exports.product_files_upload = function (req, res) {
    if (req.files) {
        var tmpArray = [];
        for(var file in req.files){
            console.log(file)
            if (file){
                var splitName = file.split('-');
                if (splitName.length > 1) {
                    var username = splitName[0];
                    var productId = splitName[1];
                    var index = splitName[2];
                } else {
                    return;
                }
            } else {
                return;
            }
            //console.log(username)
            //console.log(productId)
            var tmp_path = req.files[file].path;
            console.log(fs.existsSync(tmp_path))
            createUserDir();
            createProductDirs(username, productId);
            //console.log(__dirname)
            var target_path = './public/user_files/'+ username + '/products/'+productId+'/files/' + req.files[file].name,
                save_path = 'user_files/'+ username + '/products/'+productId+'/files/' + req.files[file].name;
            if (fs.existsSync(target_path)) {
                tmpArray.push({exists:true, name:req.files[file].name});
            } else {
                tmpArray.push({
                    size: req.files[file].size,
                    type: req.files[file].type,
                    name: req.files[file].name,
                    path: save_path,
                    exists:false
                });
                if (fs.existsSync(tmp_path)) {
                    fs.rename(tmp_path, target_path, function(err) {
                        if (err) throw err;
                        // delete the temporary file, so that the explicitly set temporary upload dir does not get filled with unwanted files
                        fs.unlink(tmp_path, function() {
                            if (err) throw err;
        //                    res.send(save_path);

                        });
                    });
                } else {
                    tmpArray.push({
                        size: req.files[file].size,
                        type: req.files[file].type,
                        name: req.files[file].name,
                        path: save_path,
                        exists:false
                    });
                }
            }
        }
        res.json(tmpArray);
    }

};

UPDATE: I am using forever for running my express app, and when I stopped my app forever process and switched to just "node app.js" the problem was fixed. This is not an acceptable fix. I am thinking there might be a problem with forever.