Cyan's English Translation:
No translation provided.
Raw D'ni Translation:
The seals seventeen
fah  bree  sen  tor  vaht  vahgahfah  vahgahbree  vahgahsen  vahgahtor  nayvoo  naygahfah  naygahbree  naygahsen  naygahtor  heebor  heegahfah  heegahbree 
one 15 two 30 three 42 four 51 five 79 six 103 seven 124 eight 152 nine 188 ten 206 eleven 239 twelve 260 thirteen 284 fourteen 298 fifteen 310 sixteen 336 seventeen 379
Note that the term "seal" in this case refers to a signet, rather than some sort of lock.
This text has been one of the greatest mysteries of the map since it was first discovered. Thanks to the ability to now enter the top of the Great Shaft (Myst V), we now have a better sense of what it means. In the Shaft, there is a marker of some kind affixed next to the entrance; most likely, this is the D'ni symbol that Atrus saw in the beginning of The Book of Atrus. It is the same as the image that contains the volcano text, which indicates that the image itself is a signet seal, or somah. By the virtue of the numbers, it is most likely the eighteenth seal.
The jury is still out on the numbers themselves. Some posit that they are the times needed from the start of the tunnel to reach that particular seal. To me, however, they still seem like a form of mile marker. Granted, the D'ni might have considered time to be more important than distance in this case; you'll note that we have a timepiece on the map, but no distance measuring implements.
The signet seals themselves may all look like the volcano text. Since we have not discovered but one, it is hard to say. According to the map, one should be located in the Great Shaft somewhere, though I have not been able to locate it, if it exists.
Line by Line Breakdown:
Due to lack of complexity, no breakdown is provided for this translation.