This error indicates that Web Access cannot correctly load one of the columns your user attribute has stored for your searches, specifically one of the columns that you have sorted on in the past. Looking at your screenshot, you are using multi-column sort, which the desktop Client does not currently support, so Client is just ignoring the sort column info that is giving WA issue.

I'm not sure what exactly is going wrong, but the associated user attribute is XMLColumnDisplay (there may be multiple attribute like this if you use different column sets for each folder). You could either look at the contents of that attribute to try to find the problematic column, or just delete all the XMLColumnDisplay attributes.

Example of the attribute (spacing added for readability):

<?xml version="1.0" encoding="utf-8"?>
<columndisplay>
	<layouts>
		<layout id="1">
			<columns>
				<column Type="System" ColCode="N" Width="202" SortPriority="1" SortOrder="A" />
				<column Type="System" ColCode="P" Width="72" />
				<column Type="System" ColCode="D" Width="82" />
				<column Type="System" ColCode="C" Width="153" />
				<column Type="System" ColCode="L" Width="153" />
				<column Type="System" ColCode="V" Width="125" />
				<column Type="System" ColCode="T" Width="126" />
			</columns>
		</layout>
		<layout id="2">
			<columns>
				<column Type="System" ColCode="N" Width="179" SortPriority="1" SortOrder="A" />
				<column Type="System" ColCode="U" Width="74" />
				<column Type="System" ColCode="H" Width="293" />
				<column Type="System" ColCode="P" Width="70" />
				<column Type="System" ColCode="D" Width="81" SortPriority="2" SortOrder="A" />
				<column Type="System" ColCode="L" Width="155" />
				<column Type="System" ColCode="V" Width="115" />
				<column Type="System" ColCode="T" Width="115" />
				<column Type="Field" Field="Document" Width="50" />
			</columns>
		</layout>
	</layouts>
	<allfolders layoutid="1" />
	<search layoutid="2" />
</columndisplay>

Here the search columns have layoutid 2, which is sorting on name (ColCode N) and Indexed (ColCode D)