I did a little more looking into the log file. The 581 error seems to be caused because Bootwiz is looking for the following file and it's not there.
D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\WINPE2\wimgapi.dll
Bootwiz also seems to be looking for some language files that don't exist as well.
2013/06/24 07:54:23 D: CBootWizardApp::LoadLanguageDLL (sBaseName='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\BootWiz', sLangCode='en', bShowError=0) - Loading language resources for 'en'
2013/06/24 07:54:23 D: CBootWizardApp::LoadLanguageDLL - Language resources loaded from 'D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\BootWiz_en.dll'
2013/06/24 07:54:23 D: CBootWizardApp::LoadLanguageHelp - Trying to load help file D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\BootWiz_en.chm
2013/06/24 07:54:23 D: CBootWizardApp::LoadLanguageHelp - Trying to load help file D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\BootWiz.chm
2013/06/24 07:54:23 D: CBootWizardApp::LoadLanguageHelp - Trying to load help file D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\BDC_en.chm
2013/06/24 07:54:23 D: CBootWizardApp::LoadLanguageHelp - Trying to load help file D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\BDC.chm
2013/06/24 07:54:23 I: CBootWizardApp::InitInstance - call to LoadLanguage failed
And finally I found these lines, I'm not sure if they are relevant.
2013/06/24 07:54:23 I: .-CPlatforms::InitPlatforms - Platform count=8
2013/06/24 07:54:23 I: . LINUX_X86 (LINUX>LINUX>LINUXPE-X86) Status=NotInstalled Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\linuxx86.ini'
2013/06/24 07:54:23 I: . LINUX_X64 (LINUX>LINUX>LINUXPE-X64) Status=NotInstalled Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\linuxx64.ini'
2013/06/24 07:54:23 I: . WINPE21_X86 (WINPE>WINPE2>WINPE21-X86) Status=NotAvailable Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\WinPe2X86.ini'
2013/06/24 07:54:23 I: . WINPE21_X64 (WINPE>WINPE2>WINPE21-X64) Status=NotAvailable Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\WinPe2X64.ini'
2013/06/24 07:54:23 I: . LINPROD_X86 (LINPROD>LINPROD>LINPROD-X86) Status=NotAvailable Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\LinX86.ini'
2013/06/24 07:54:23 I: . LINPROD_X64 (LINPROD>LINPROD>LINPROD-X64) Status=NotAvailable Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\LinX64.ini'
2013/06/24 07:54:23 I: . WINDOWS_X86 (WINDOWS>WINDOWS>WINDOWS-X86) Status=NotAvailable Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\WinX86.ini'
2013/06/24 07:54:23 I: . WINDOWS_X64 (WINDOWS>WINDOWS>WINDOWS-X64) Status=NotAvailable Ini='D:\Program Files\Altiris\Altiris Agent\Agents\Deployment\Task Handler\Bootwiz\Platforms\WinX64.ini'
2013/06/24 07:54:23 I: .-CPlatforms::InitPlatforms - Hidden platform count=0
2013/06/24 07:54:23 I: .<CPlatforms::InitPlatforms - returning 1 (success = 1)