Trying to add a new category, it gives the error "Guid should contain 32 digits with 4 dashes". After doing lots of research and debugging on this issue, found the problem in the following lines of code inside "/admin/Posts/Categories.aspx.cs"
void btnAdd_Click(object sender, EventArgs e)
Category cat = new Category(txtNewCategory.Text, description);
if (ddlNewParent.SelectedValue != "0")
cat.Parent = new Guid(ddlNewParent.SelectedValue);
For some reason ddlNewParent.SelectedValue gets the empty string either you select the "none" category or any existing category or nothing. I am still not able to figure out the issue but if I comment out the "if(...)" condition, then I can create a new category.
FYI, I am using BE 2.0 with MS SQL database. Thought it might be a bug which hasn't been yet identified or fixed. Please let me know if this issue is already fixed or someone fix it soon.