I am using silverstripe v2.2.2.I install blog widget and then I run db/build.
I am getting following error

<i>
FATAL ERROR: Bad class to singleton() - BlogEntry
At line 85 in C:\wamp\www\silverstripe\sapphire\core\Core.php

user_error(Bad class to singleton() - BlogEntry,256)
line 85 of Core.php

singleton(BlogEntry)
line 175 of DatabaseAdmin.php

DatabaseAdmin->doBuild()
line 90 of DatabaseAdmin.php

DatabaseAdmin->build(Array)
line 261 of Controller.php

Controller->run(Array)
line 104 of Director.php

Director::direct(/db/build)
line 158 of main.php

Context

--------------------------------------------------------------------------------

Debug (Debug::showError() in line 180 of Debug.php)
className =
BlogEntry
_SINGLETONS =
Newsletter =
Database record: Newsletter
ID :
0
Newsletter_SentRecipient =
Database record: Newsletter_SentRecipient
ID :
0
Newsletter_Recipient =
Database record: Newsletter_Recipient
ID :
0
NewsletterType =
Database record: NewsletterType
ID :
0
PageComment =
Database record: PageComment
ID :
0
Email_BounceRecord =
Database record: Email_BounceRecord
ID :
0
Email_BlackList =
Database record: Email_BlackList
ID :
0
PageView =
Database record: PageView
ID :
0
SiteTree =
Database record: SiteTree
ID :
0
Translatable = Translatable::__set_state(array( 'translatableFields' => array ( 0 => NULL, 1 => true, 2 => NULL, 3 => NULL, 4 => NULL, 5 => NULL, 6 => NULL, 7 => NULL, 8 => NULL, ), 'original_values' => NULL, 'owner' => NULL, 'extension_instances' => array ( ), 'class' => 'Translatable', ))
QueuedEmail =
Database record: QueuedEmail
ID :
0
File =
Database record: File
ID :
0
EditableCheckboxOption =
Database record: EditableCheckboxOption
ID :
0
EditableDropdownOption =
Database record: EditableDropdownOption
ID :
0
EditableFormField =
Database record: EditableFormField
ID :
0
EditableRadioOption =
Database record: EditableRadioOption
ID :
0
SubmittedForm =
Database record: SubmittedForm
ID :
0
SubmittedFormField =
Database record: SubmittedFormField
ID :
0
Group =
Database record: Group
ID :
0
Member =
Database record: Member
ID :
0
Member_UnsubscribeRecord =
Database record: Member_UnsubscribeRecord
ID :
0
Permission =
Database record: Permission
ID :
0
Widget =
Database record: Widget
ID :
0
WidgetArea =
Database record: WidgetArea
ID :
0
Page =
Database record: Page
ID :
0
GhostPage =
Database record: GhostPage
ID :
0
</i>
I dont know where I am goin wrong.Please help.