The mode that you have set should not be used, IE will never turn to that mode on its own. This means that your users's browsers wont work into that mode unless explicitly forced. The modes, that IE is expected to be used with, are:
1) Browser mode IE Standards ; Document mode IE 8 standards - RadUpload will work as expected.
2) Browser mode IE Compat View ; Document Mode IE 7 standards RadUpload will work as expected.
Browser Mode IE Compat view ; Document mode - IE8 standards - RadUpload wont' work in all cases. However, keep in mind that this mode can be hardly turned on by the regular user. I suggest that you change your meta directive so that it no longer forces the browser to be in standards mode. If your pages have property <doctype> directive IE will automatically turn on the respective mode.
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