Can't see objects in RSA1

Hi,

Why I can't see some objects in Administrator Workbench? For example when I try to make InfoObject the system says that it is already created, but I can't see it in any of InfoObject tree nodes. When I try to assign a DataSource to SourceSystem, the system says 'The DataSource is already assigned to InfoSource 0MATERIAL_ATTR', but I can't see the assigment. Is it a problem of bad installation of some latest patches?

Regards,

Maciek