Ok, after few more trials & errors, i found that .tp file with subtitle works in PDVD10.
It is the .srt that is not fully supported by PDVD10 (.srt with special/additional effect i believe). the .srt works perfectly under kmplayer, but not in PDVD10. PDVD10 will not even show the option of subtitle if it is unicode (for that particular .srt). If it is non-unicode, PDVD10 will show the subtitle option, but display alien words.
For .srt without special effect, PDVD10 is able to display it correctly.
I use kmplayer to save the .srt subtitle into .smi and it is working in PDVD10 now. Special effect has been removed while convertion i think.