I don't know what this error means, but I got this error:

[Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[Client thread/ERROR]: ########## GL ERROR ##########
[Client thread/ERROR]: @ Post render

and ten seconds after that:

[16:13:48] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:13:48] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named InSize in the specified shader program.
[16:14:01] [Client thread/WARN]: Could not find uniform named Time in the specified shader program.

(I know thís error is reported already)