Try to save your file in the same folder of the phylip program. Anyway MEGA software is easier to work with and there are lots of guides avilable on the internet.

Try to save your file in the same folder of the phylip program. Anyway MEGA software is easier to work with and there are lots of guides avilable on the internet.

Besides Mega, which gives a lot of options, you can use geneious which is really user friendly.

PHYLIP programs (DNADIST, PROTDIST, NIEGHBOR, etc..) each exist as separate modules that do one task each, which is great for using scripting or programming to automate the analyses of hundreds of data sets.   Other phylogenetic "packages" such as MEGA, DAMBE, GENEIOUS etc. provide a "system" within with the user uses pull-down menus (Graphical User Interface) to tell the system which files to use and what do do with them.

If you have reasons for using PHYLIP, rather than MEGA or some other software that is easier for most people to use, you might try a GOOGLE search for [PHYLIP tutorial] and try some of those results.  The default for most PHYLIP programs is that it will look for "infile" and will produce "outfile" and if your input is not named "infile" then you need to tell the DNADIST program the exact path and filename of your input file.  This is easier if the input file is in the same directory as the DNADIST program so you do not need to specify the path.

I am recently also using "dnadist" in Phylip program, the file format is quit strictly required. check the manual page of "dnadist" first.

if this still doesn't work, another tricky thing is you can not leave gap( or any blank) after you typed the  phylip file name before you press Enter

such as:

Please enter a new file name> /Applications/phylip-3.695/exe/1psba194.phy

dnadist: can't find input file "/Applications/phylip-3.695/exe/1psba194.phy "

the right way is :

Please enter a new file name> /Applications/phylip-3.695/exe/1psba194.phy

check the blank after the file name

hope it helps.