Notice this: tow prophecies in sequence same like above ... even same sequence ..
Seir --> from mount Paran (which is a group of mountains it's not specified) then after (you see the verses it was specified by the exact area)
Isaiah 21
11 The oracle concerning Dumah. One is calling to me from Se'ir, "Watchman, what of the night? Watchman, what of the night?" 12 The watchman says: "Morning comes, and also the night. If you will inquire, inquire; come back again." 13 The oracle concerning Arabia. In the thickets in Arabia you will lodge, O caravans of De'danites. 14 To the thirsty bring water, meet the fugitive with bread, O inhabitants of the land of Tema.




see the bible explanation :: http://bible.cc/isaiah/21-14.htm (you go and check by yourself)

* Tema was one of the sons of Ishmael Genesis 25:15, and is supposed to have populated the city of Thema in Arabia Deserta. The word denotes hero one of the tribes of Ishmael, or of the Arabians.

* The idea is, that the inhabitants of the land would be oppressed and pursued by an enemy; and that the Arabians, referred to by the prophet Isaiah 21:13, would be driven from their homes; and be dependent on others; that they would wander through the vast deserts, deprived of the necessaries of life; and that they would be dependent on the charity of the people of Tema for the supply of their needs.


Now let us see what is the race of Prophet Mohamed from wikipedia:

http://en.wikipedia.org/wiki/Qusai_ibn_Kilab

Now Let us read the rest of verses :
Isaiah 21
13 The oracle concerning Arabia. In the thickets in Arabia you will lodge, O caravans of De'danites. 14 To the thirsty bring water, meet the fugitive with bread, O inhabitants of the land of Tema. 15 For they have fled from the swords, from the drawn sword, from the bent bow, and from the press of battle. 16 For thus the Lord said to me, "Within a year, according to the years of a hireling, all the glory of Kedar will come to an end; 17 and the remainder of the archers of the mighty men of the sons of Kedar will be few; for the LORD, the God of Israel, has spoken."

Now read the story of Hijra for Prophet Mohamed : (Hijra means to travel from place to another)
Hijra::: http://en.wikipedia.org/wiki/Muhammad#Hijra