Regardless of your condition of server admin (if this is what you meant), you need to check that you have the adequate "tiki" permissions:
|tiki_p_admin_sheet||sheet||Can admin sheet|
|tiki_p_edit_sheet||sheet||Can create and edit sheets|
|tiki_p_view_sheet||sheet||Can view sheet|
|tiki_p_view_sheet_history||sheet||Can view sheet history|
Ensure that your tiki user you are running as (whichever it is, even if it's the "admin" initial user) has the needed right in its group (seems as if tiki_p_view_sheet was missing for the group of that user?)
The last thing I can think of is that you were using an theme style from older tiki distros (1.8.x, at the most), that hasn't been updated with the css information for tikisheets.
Try showing your tikisheet page in a different theme style (such as moreneat or tikineat).
If none of this helps to solve the "mistery", I would suggest to report a bug at http://dev.tikiwiki.org (unless any other user or admin get's where the problem may be)