I have tried updating the SVAR add-on package to version 1.96 on my PC, yet the problem still persists. In fact, the bugs have compounded; the help pdf file could not even be opened, even from another PC. 

Find below the error messages:

C:\Users imme\AppData\Roaming\gretl\irf768.gp: Invalid argument
*** error in function IRFgrph, line 34
> outfile "C:\Users imme\AppData\Roaming\gretl\irf768.gp"
 called by function IRFsave
*** error within loop in function IRFsave
> tmpfile = IRFgrph(IRFmat, snum, vnum, scale, sn, yn, keypos, null, &boot, bc, whichdraw)
 called by function IRFplot
 called by function GUI_plot

C:\Users imme\AppData\Roaming\gretl\fevd9937.gp: Invalid argument
*** error in function FEVDgrph, line 22
> outfile "C:\Users imme\AppData\Roaming\gretl\fevd9937.gp"
 called by function FEVDsave
*** error within loop in function FEVDsave
> string tmpfile = FEVDgrph(Fmat, vnum, obj.Ynames[vnum], obj.snames, keypos, titletail)
 called by function FEVDplot
 called by function GUI_plot

C:\Users\timme\AppData\Roaming\gretl\.mysession\functions.pdf: No such file or directory