Adobe Acrobat freezes on Thinapp 5.1

Hi.

Thinapped Adobe Acrobat X (XI) freezes on listing pdf file.

This happens only with ver. 5.1. Acrobat thinapped with ver. 5.0 and 5.0.1 works fine.

Pdf file has 400 pages (~20 Mb).

Maybe someone else faced a similar problem?