Your server does not have GD2 installed and your telling the program to use GD2 as the processor in global options in admin. You need to do one of the following.
1. recompile php with gd support.
2. find if your server has imagemagick installed or install it and set the proper full server path to mogrify in edit config in admin.
You can then set in global options which imageprocessor to use but you need one on your server to process images.
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