QUOTE(uunmatal tarunno @ Apr 25 2008, 06:21 AM)

Is this problem happening to particularly for this document or other Bangla documents also?
Try to change bangla fonts like, Solaimanlipi or siyum rupali and try again.
I am not certain but this can be happened for the Arabic text in this document. If you look carefully, your font is showing Traditional Arabic and the Bangla text is showing in "Vrinda" which is system (Windows) default for Bangla. Another font named "Arial Unicode" is default for MS Office, which has particularly this kind of ত+ু, ম+ি problem. I guess these are conflicting and causing the mess.
Try it with different font.
I had the same problem with other Bengali documents, I don't believe the Arabic text was an issue in this case. I tried Siyam Rupali anyway without any success. Alhamdulillaah (শমস্ত প্রশংশা আল্লাহর), SulaymanLipi did the job for me. Jazak-Allaahu khayraa (may Allaah reward you well) for supporting me, may He give you the ability to co-operate with others in good works also. Ameen.