I would be curious what version of the script you are trying to use.
I definitely fixed everything with it after the EasyUO updates which changed the menu code.
I have it working on many freeshards and the production servers as well.
There are many reasons why it may not work. You need a valid version of the script though to handle the gump when the SOS is opened. OSI/Production, RunUO2.0, ServUO (versions 57.x and 58) have all been working for me, but the gump can be different.
Plotting the dots is independent of being able to sail to the proper location. The data is stored that gives the coordinates of the map location. Your person has to be on the map location and then can fish it up from anywhere around it. The important part is that your specific tile location match the MIB/SOS location. Which direction around you doesn't matter when fishing.
Is it plotting points for your maps?
The script will calculate the location based on approximately 4 quadrants: NW, NE, SW and SE (it is a little weird at the right most edge of the map, because you end up with NW and SW crossing over to the far right). There is an issue where some of the gumps have the map location within the text of the SOS, while others have it fixed on the SOS gump. Then there is an issue where some gumps always have some additional text and seem to force all maps to be pinned either North or South (I forget, but I suspect it is plotted and calculated as North) which leaves some correct and others wrong.
Maybe you would like to share which freeshard and a description of what is happening?