The most likely reason is that you've linked your Flickr account to BigHugeLabs.com and when you did you chose to keep your photos private. Since the Profile Widget is intended for public display, it is incompatible with that setting. Click here to change your BigHugeLabs privacy setting.

If your widget shows your screen name and stats but doesn't show any of your photos then the problem is that your photos are private. The widget only shows public photos.

It could be that you've specifically flagged your photos as private (friends and family only). Or it could be that your photos or account are flagged by Safe Search as "moderate" or above. See this FAQ for more information: http://www.flickr.com/help/filters/

Profile widgets are cached to improve performance. Widget are not updated every time they are viewed. Widgets update at a varying frequency that depends on several factors including how often they are viewed (that is, the more frequently a widget is viewed, the more frequently it is updated).

The most likely reason your Profile Widget wouldn't show up after pasting it into your profile is that you've copied the HTML incorrectly or incompletely. Accidentally leaving out a single character could cause the widget to malfunction.

However, some non-Pro Flickr members seem to randomly have issues inserting images into their profile. You can find some workarounds here.

Scout can show you which of your photos are in Explore at this moment and which have ever been in Explore (including ones that are no longer there).

The profile widget only shows the count of photos that are currently in Explore. However, the number may be slightly different than what you were expecting because widgets are cached to improve performance and are not updated every time they are viewed (unlike Scout). See "Why isn't my Profile Widget updating" for an explanation of widget update frequency.