The lack of positive earlier relationships, the negative cognition, and the somatic responses are all redflags. You have described a client that would probably have greatly benefited from more stabilization work that included the incorporation of positive resources and templates. The blocked response you are encountering when targeting present events is generally attributed to either the "well spring phenomena" of additional earlier events that are contributing to the anxiety that are not being accessed, and/or the lack of positive information needed to continue the processing.
You might want to: (a) review the pertinent sections of the EMDR textbook (Shapiro, 1995, Guilford Press), (b) attend the EMDRIA Conference presentation of Andrew Leeds on the use of EMDR for "Resource Development and Installation" (I believe he is also doing a day-long presentation incorporating that topic at the Menninger Clinic), (c) review pertinent chapters in "Extending EMDR: A casebook of innovative applications" edited by Philip Manfield (1998, Norton) and (d) join the EMDR discussion list which is available to you if you are a graduate of the EMDR Institute (see http://www.emdr.com for information). This will give you access to on-going case consultation and support.
It is important to remember that clients constitute a bell-shaped curve. While approximately 90% of single-trauma victims are freed of the PTSD diagnosis in three sessions, complex anxiety disorders, expecially those grounded in early abuse or neglect must be dealt with in a more comprehensive fashion. The standard EMDR protocol of "past/present/future" is not applicable to the more dysfunctional clients until after a suitable stabilization period, and the incorporation of accessible positive affects and resources.