Fixed with April 2011 Cumulative Update!
The errors returned from the queue are as follows:
Error ID: 23006
Error ID: 26000
Detailed error below - send it to the administrator for more detailed troubleshooting.
<?xml version="1.0" encoding="utf-16"?>
<errinfo>
<array name="rejectedTimesheetLines" type="System.Guid">
<item value="c1ceebb4-cb2d-0a3a-1672-12f252da3df5">
<error id="10000" name="GeneralItemDoesNotExist" uid="6d4f206a-49b1-43cf-bd8f-af2d84c22e7d" />
<error id="10000" name="GeneralItemDoesNotExist" uid="bec86fdb-b855-45e5-8d66-77078f724e10" />
<error id="10000" name="GeneralItemDoesNotExist" uid="14d3a002-371d-49e5-ab31-102826f3a72e" />
<error id="10000" name="GeneralItemDoesNotExist" uid="3a9b9ab4-9037-4742-a002-057e8382429a" />
<error id="10000" name="GeneralItemDoesNotExist" uid="7d5e43b0-e0e4-4d47-930c-e60e3c53a971" />
<error id="10000" name="GeneralItemDoesNotExist" uid="47f539d7-202e-435a-abda-fdb1b50d8478" />
</item>
<item value="c6f9fbc1-bb71-4921-a42a-14484fb56a95">
<error id="10000" name="GeneralItemDoesNotExist" uid="450274a1-7be1-47e4-9e32-a2de06918bf9" />
<error id="10000" name="GeneralItemDoesNotExist" uid="3832a908-8dd6-4ee0-bacf-5729f3dbc693" />
<error id="10000" name="GeneralItemDoesNotExist" uid="0f2e4415-1859-4ac2-8787-cb5493e6f79b" />
<error id="10000" name="GeneralItemDoesNotExist" uid="9f85e582-311a-4c4f-add5-bba59b509b92" />
<error id="10000" name="GeneralItemDoesNotExist" uid="d976f5cd-f77e-447f-95fa-4b95ba2dcac5" />
<error id="10000" name="GeneralItemDoesNotExist" uid="64993abb-e268-4cc3-8fcd-eb70cfc1784a" />
</item>
<item value="85f9c4ce-38e5-0589-23a1-1bc4849a4a7e">
<error id="10000" name="GeneralItemDoesNotExist" uid="16946d36-a6bf-433a-8048-abb254a950c9" />
<error id="10000" name="GeneralItemDoesNotExist" uid="13dffe7f-1000-447c-971c-2a02bcb97e0f" />
<error id="10000" name="GeneralItemDoesNotExist" uid="aab97ce8-0bc9-4e4e-8c42-e704b34ee493" />
<error id="10000" name="GeneralItemDoesNotExist" uid="49a6838f-713d-4302-9815-ca691d638d8d" />
<error id="10000" name="GeneralItemDoesNotExist" uid="c65126ad-48a6-4566-a895-a90deb568b47" />
<error id="10000" name="GeneralItemDoesNotExist" uid="bf355b10-2c05-4300-9f1e-db7bcf3c58ee" />
</item>
<item value="97c5a71e-2d4b-474e-a942-1d4c2b2cd3f5">
<error id="10000" name="GeneralItemDoesNotExist" uid="a5b1c17b-4a06-45df-bb7f-bea90aec8eb2" />
<error id="10000" name="GeneralItemDoesNotExist" uid="cbc213ff-7a59-4cff-9131-beae4f7acd9b" />
<error id="10000" name="GeneralItemDoesNotExist" uid="527ba6a1-f010-43d9-945b-5405f22c91e1" />
<error id="10000" name="GeneralItemDoesNotExist" uid="5351cc2b-ef65-47a0-96a2-5b69d3a1b5bb" />
<error id="10000" name="GeneralItemDoesNotExist" uid="9f02f7a6-45dc-4f03-ac80-d96f5ea46c57" />
<error id="10000" name="GeneralItemDoesNotExist" uid="6da5c9af-a65b-4795-8bc2-ecc5bdf93c57" />
</item>
<item value="6f74c014-9a02-4ebe-bd6d-2551538f20ed">
<error id="10000" name="GeneralItemDoesNotExist" uid="a06a1619-5f72-4c98-8601-a7b224e6189d" />
<error id="10000" name="GeneralItemDoesNotExist" uid="47eb60ea-d6ac-4756-9ed3-e8dd2819bb56" />
<error id="10000" name="GeneralItemDoesNotExist" uid="157bc6f2-ce50-4caa-ae6c-13be5770ab11" />
<error id="10000" name="GeneralItemDoesNotExist" uid="06bcccf5-aa37-49a7-b9d9-f0fea649f603" />
<error id="10000" name="GeneralItemDoesNotExist" uid="7833f227-f956-461d-be76-a2c3ff5ed2bd" />
<error id="10000" name="GeneralItemDoesNotExist" uid="c5c197c6-ac64-455f-a10d-743ce3962dd3" />
</item>
<item value="cfd7b461-5680-0efa-26a7-29666b937316">
<error id="10000" name="GeneralItemDoesNotExist" uid="6db1f88b-6c2e-4903-a180-00f71a0f5362" />
<error id="10000" name="GeneralItemDoesNotExist" uid="f45a3c42-5cf7-4e12-a207-beb58a7d03d9" />
<error id="10000" name="GeneralItemDoesNotExist" uid="77b5222b-21b8-4676-a905-63197db1e37a" />
<error id="10000" name="GeneralItemDoesNotExist" uid="d6660605-3758-4155-bd81-001f9a224f98" />
<error id="10000" name="GeneralItemDoesNotExist" uid="8f344b05-5b77-4e18-8296-2fde36f271d6" />
<error id="10000" name="GeneralItemDoesNotExist" uid="9a349fd7-d221-4b57-8533-ecde7400e24e" />
</item>
<item value="6536d41a-e194-0a4e-099d-2d380173cf6b">
<error id="10000" name="GeneralItemDoesNotExist" uid="d469afca-b4e9-4a04-b36c-466f285d2ed9" />
<error