Hi.. First I've installed widget but not the blog. Subsequently I've deleted widget and now I try to install BLOG 0.1 but I can't do it. There is an error. The server say:

"Warning: Cannot modify header information - headers already sent by (output started at C:\wamp\www\silverstripe-v2.2.2\silverstripe-v2.2.2\blog\code\BlogEntry.php:52) in C:\wamp\www\silverstripe-v2.2.2\silverstripe-v2.2.2\sapphire\core\Debug.php on line 151

Error
The website server has not been able to respond to your request."

How can I do for install Blog and widget?

Thank you..

Yes, I do. When I run /db/build/?flush=1 I read that written

I've tried do modify it. I've tried besides to delete the written

Director::set_dev_servers(array(
   'localhost',
   '127.0.0.1',
));

with the written

Director::set_environment_type("dev");

and the result is the same. It appears:

FATAL ERROR: Bad class to singleton() - BlogEntry
At line 85 in C:\wamp\www\silverstripe-v2.2.2\silverstripe-v2.2.2\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 =
Member =
Database record: Member
ID :
0
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
Post =
Database record: Post
ID :
0
Post_Subscription =
Database record: Post_Subscription
ID :
0
GalleryPage_Extension =
Database record: GalleryPage_Extension
ID :
0
MemberLocation =
Database record: MemberLocation
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_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've tried to do it but there is a new message that says me there is an error in the first line. I've already tried to insert your written at the top but this time into the pre-existent inverted comma. In this case there is the usual error. I think there is an error becaouse first I've installed widget and after blog. Now I've deleted widget but I can't install blog!