Hi,

I'm having a bit different problem, but the error message is exactly same as yours:
"Fatal error: Class name must be a valid object or a string in (root)/concrete/startup/process.php on line 858"

Did you manage to solve this issue?

not properly
i have used the "russian method" of solving problems, i have bypass it as possible.... i have uninstall all addons and then install them again...
if u have guestbook or forms added to ur website... cancell them from ur pages and re add them again.
now the site works again ... i dont know exactlly where the problem was.. some guys on forum tald to me that could be flash player.. so u can just uninstall any flash driven add on...
let me know if u solved the problem.

gl pal

I'm still in early stage of making website on my local, so it's not that bad if I have to re-install, yet quite annoying, isn't it!

I don't have any add-on you suggested, but I'll give a try uninstall all.

Thanks for quick reply!

no problem

try to reinstall also the flash player on ur p.c. ... maybe will help. uninstall from Add/Remove programs from Control Panel of ur Windows os... and after that install Flash player from YouTube link...
try this.. hope it will help :-/

...hmmm not a big use of my advice... now are those addons that i have reinstalled a week ago starts to fail again! nice, very nice!!!

Okay, it's working SO FAR, and I really don't know what solved it.

Note for reference.

Problem:
A certain block wasn't displaying on browers other than Safari (Everything looks good and working on Safari). Using Firefox, I tried to add a block of the add-on but got an error "Fatal error: Class name must be a valid object or a string in (root)/concrete/startup/process.php on line 858."

My environment:
Concrete5 vr. 5.5.2.1 on a local drive using MAMP

Things I did:
1. Uninstall all add-ons and released from project using Safari. (Got an error using Firefox.)

2. Cleared cache

2. Updated Shockwave plug-in, but could not update Flash Player since the machine used for the project is old + old OS and Flash Player no longer supports it.

3. Using Firefox, associated the add-on I released earlier and installed.
Not sure if this matter, but I had to re-connect the project using Firefox even though it's already connected with my account when I use Safari.
Then, I notice there're 2 projects created under My concrete5 Sites. "http://localhost:80/" when I used Safari and "http://localhost/" on Firefox. So I released add-on from "http://localhost:80/" and associated to "http://localhost/"

*magic*

working.
and hopefully keep working.

best,
H

hi
iam glad u solved...
my problems pop up when i pubblished my website online(uploaded on a commercial provider-webspace/domain), while i was building the theme and scripting CSS/HTML locally on my p.c. i had not any of this problems... i am using the last WampServ, and was always working nicelly... maybe is the php/mysql/apache versions that doing those errors on C5

its local(flash/java/shockwave..incompatibility with browser ) problem... in Firefox some addons dont work, on IEx64 works correctly..