1. Can't load property type 'EPiServer.Fields.LongString, EPiServer.Fields'.

2. FAILED The scheme for the url "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAASoAAADRCAIAAAD0emgWAAAgAElEQVR4nOydZ0AT2drHs9Xd9W6/u3vv3X636zbb2hV17b0gFlBAKQLSq9I7UqVKFQUEpPfee2+hJKSQEBKSkF4nmZnzfsC+6IKCd+978/ugw8w5M0+S+c+c8jzPwYCnBH1wG73z5/QGercE+nAxFSpUPARmAc6pkpwKFbNiIeSnQoWKWaGSnwoV/" in not http or https.

Take a look at the following post and see if the suggestions works http://world.episerver.com/Modules/Forum/Pages/Thread.aspx?id=61001

Add this to <excludePatterns> to see if it helps:
<excludePatterns>
<add regex=".*doc"/>
<add regex=".*pdf"/>
<add regex=".*png"/>
<add regex=".*jpg"/>
<add regex=".*jpeg"/>
<add regex=".*gif"/>
<add regex=".*data-dynamicclass"/>
<add regex="^\."/>
<add regex="^\/"/>
<add regex="^cel" />
<add regex="^Documents" />
<add regex="^file" />
<add regex="^javascript" />
<add regex="^outbind" />
<add regex="^httphttp" />
<add regex="^EPiServer.Fields.LongString, EPiServer.Fields" />
</excludePatterns>

Here is one sql query to find unusal links in the database:
SELECT * FROM tblpageSoftLink WHERE LinkURL NOT LIKE '~/link%' AND LinkURL NOT LIKE 'http://%' AND LinkURL NOT LIKE 'mailto%' AND LinkUrl NOT LIKE 'https://%' ORDER BY LinkUrl ASC