Unable to load ff99SBdisp in Amber 20 tleap

[Shura58]

Hi All,
I'm trying to use the ff99SBdisp force fields with Amber20. All relevant files from GitHub have been copied to the cmd, lib and parm directories of the Amber installation tree.
However, when I try to load the leaprc files tleap crashes with a syntax error:
`> source leaprc.protein.ff99SBdisp
----- Source: /home/gard/Code/amber20_src/dat/leap/cmd/leaprc.protein.ff99SBdisp
----- Source of /home/gard/Code/amber20_src/dat/leap/cmd/leaprc.protein.ff99SBdisp done

/home/gard/Code/amber20_src/bin/teLeap: Fatal Error!
Error from the parser: syntax error

Exiting LEaP: Errors = 1; Warnings = 0; Notes = 0.
`

The same happens when loading leaprc.water.tip4pd_disp. Tleap doesn't write any logs with additional information. Can you think of a possible reason for this?

Thank you in advance

Sasha