Crash when searching for some specific items from other mods

[BorisMulder]

In a SMP game, I get a client crash when executing some query searching for all items from OpenComputers by typing @OpenComputers in the NEI search bar:

java.lang.NoSuchMethodError: net.minecraft.item.ItemStack.getItem()Lnet/minecraft/item/Item;
	at net.moecraft.nechar.NecharSearchFilter.matchesMod(NecharSearchFilter.java:83)
	at net.moecraft.nechar.NecharSearchFilter.matches(NecharSearchFilter.java:73)
	at codechicken.nei.ItemList$AnyMultiItemFilter.matches(ItemList.java:112)
	at codechicken.nei.ItemList$AllMultiItemFilter.matches(ItemList.java:87)
	at codechicken.nei.LayoutManager.renderSlotOverlay(LayoutManager.java:716)
	at codechicken.nei.guihook.GuiContainerManager.renderSlotOverlay(GuiContainerManager.java:435)
	at net.minecraft.client.gui.inventory.GuiContainer.func_146977_a(GuiContainer.java:270)
	at net.minecraft.client.gui.inventory.GuiContainer.func_73863_a(GuiContainer.java:99)
	at net.minecraft.client.renderer.InventoryEffectRenderer.func_73863_a(InventoryEffectRenderer.java:38)
	at com.bioxx.tfc.GUI.GuiInventoryTFC.func_73863_a(GuiInventoryTFC.java:189)
	at net.minecraft.client.renderer.EntityRenderer.func_78480_b(EntityRenderer.java:1061)
	at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1001)
	at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:898)
	at net.minecraft.client.main.Main.main(SourceFile:148)

while this might be an OC issue (which I doubt), it also happens when I login and open my inventory again with the same save, resulting in an unplayable save.

1. What could be the cause of this issue? Is it an OC or a NEI issue?
2. How can I clear the current text in my search bar from my save game? Is this info stored somewhere on the client side or also on the server side?