If your machine does not yet support MCN conversions, delete line 161 in BROWSE.NAMES.
If your compiler does not understand the "functional" form of the LOCATE statement, use LOCATE NODE.ID IN F<3> SETTING NODE.POS ELSE... in line 31 of BTPSEQ, and use LOCATE NID IN P<3> SETTING PS ELSE... in line 43 of BTPDEL.
If your compiler now allows an ELSE clause on WRITE statements, such as in the recent releases for C. Itoh computers, change line 38 of BTPINS to IF N<1> > (2*SIZE) THEN, and change line 89 to END ELSE WRITE N ON BFILE, NID.