When I click these two buttons,export String and import String, it's invalid. Anybody know why? Does this have anything to do with the operating system? I'm using Windows 10.

let me give you an example.
with this tool I made some fire and smoke points like that

[SmokeSection1]
Records=4
X_Y=012A0114014101160141011700EE014C

but in md file its like that
SMOKE 3 281 224 193 195 359 181
and I ve make that xy line(programs coordinates like 12A 114 141 116 141 117 0EE 14C
I know I should type some numbers for A E and C so I cant understand what number equalls to A or E or C

It's because you are reading the .iif file you have saved.
What you should do is, set up the points, then click export string and then go to a text file or md file and press control +v ( paste).
It will paste in proper x and Y coordinates (or block points, depending on the option chosen)

ahh yes. this tool is usefull if u know how ti use it. what u do is. select the blocks for whatever u want. and go to the MD, and write the block numbers down beside the entery and then the number of blocks

what is export and import string for..IM using this tool but still I cant modify building points..I need a huge tutorial about it..

Oh wow! I'll use this for my upcoming mod!

Thanks a lot for explain to me, Angel

If I good understand, by this tool I can for example: add to pikmen possibility to fire by muskets with smoke?

No Cichor, this is for buildings. To add block points, build points, smoke & fire points, exit points. This tool is there because no human can manually configure these points without going mad. Fire up an md off a building and you will see sometimes a couple of hundred of these points in pairs. Have a look at this page to the build & lock points: http://cossacksworld.ucoz.co.uk/index/0-36
Adding "fire by muskets" to a pikemen is impossible, because that is an animation.Well, not impossible, but you need the original models to do that and render the frames again to create such a fire animation.

Ofcourse, you can add 'fire points' to a unit, meaning if you kill the unit it will start going on fire, but I dont think that is realistic, nor smoke coming out off a unit