VZV IgG titer= 1926, VZV IgM titer >3.91 with reactivated shingles present. What does test mean? Active VZV infection? Is 1926 dangerously high.

No it just means. You had chickenpox previously. It is not dangerous at all . The IGm is what tell that you have reactivated and then it is called shingles. You can't have shingles if you did not have chickenpox before.
Active infection. The presence of the IgM antibiodies suggests an active varicella infection. It seems that this was going to be the case regardless as you mention that you have an active shingles rash. The IgG antibodies are suggest that you have had either an old exposure or vaccination(which you mentioned was the case). Don't get too caught up with the IgG level, it's good to produce IgG's. .