The following is a statement made by a fellow brother in Christ who proposed that the Tabernacle of David has not yet been rebuilt as prophesied by Amos 9:11.  I will show the common error of reading this brother proposes, which is touted bny dispensationalists as they attempt to prove that teh tabernacle of David is not yet rebuilt.  Note his words:
But, notice the tenses of the verbs in the 15th verse.
Act 15:16 AFTER THIS (after the gentliles are fully come in) WILL I RETURN, (yet future) and will build again (future) the tabernacle of David, which is (presently) fallen down; and I will build again (future) the ruins thereof, and I will set it up: (because it is not presently set up)
This is a very traditional and common error of intepretation regarding what "after this" refers to.

"After this" does not refer the time when the gentiles will come in.

Let us compare James' quote with the actual reference, so I can show you how this interpretation is flawed by the use of the words noted by James.

Amos 9:9-12 
For, lo, I will command, and I will sift the house of Israel among all nations, like as [corn] is sifted in a sieve, yet shall not the least grain fall upon the earth.  All the sinners of my people shall die by the sword, which say, The evil shall not overtake nor prevent us.  (11)  In that day will I raise up the tabernacle of David that is fallen, and close up the breaches thereof; and I will raise up his ruins, and I will build it as in the days of old:  (12)  That they may possess the remnant of Edom, and of all the heathen, which are called by my name, saith the LORD that doeth this.

Acts 15:13-17 
And after they had held their peace, James answered, saying, Men [and] brethren, hearken unto me:  (14)  Simeon hath declared how God at the first did visit the Gentiles, to take out of them a people for his name.  (15)  And to this agree the words of the prophets; as it is written,  (16)  After this I will return, and will build again the tabernacle of David, which is fallen down; and I will build again the ruins thereof, and I will set it up:  (17)  That the residue of men might seek after the Lord, and all the Gentiles, upon whom my name is called, saith the Lord, who doeth all these things.

You can clearly see that James substituted the words "in that day" for "after this".  And what did "in that day" refer to?  After the gentiles are come in?  No!  They refer to the time when destruction shall come when God sifts the house of Israel in punishment.  And James interpets the phrase "in that day" to be "after this", telling us that after sifting the house of Israel, the Lord would come and build up the Tabernacle of David again!   And the sifting occurred before Jesus Christ first came to Israel!  That leaves us with the understanding that there is no future coming that Amos is referring to here.  Yes, Jesus is coming again, but not to build the tabernacle of David.

Dispensationalists have twisted this idea into what has been indicated in my brother's quote, whether people knew that or not, and have made it look like the church is a gentile entity.  And after the gentiles be come in, they propose God will bring the millennium, and some other things to come.

Anyway, I think you can see my point how that "after this" does not refer to after the gentiles come in.  The coming in of the gentiles is what occurs "after this".  And that comes about because after the sifting, the Tabernacle of David is rebuilt so that the Gentiles, at that point, can come in.

Here is what our James actually said.

Act 15:16 AFTER THIS (after the house of Israel is sifted) WILL I RETURN, (which was fulfilled when Jesus came in his earthly ministry to die on the cross for ous sins) and will build again (fulfilled) the tabernacle of David, which is (in the time context after the House of Israel was sifted - future in Amos' day, but fiulfilled in James' day) fallen down; and I will build again (after the House of Israel is sifted) the ruins thereof, and I will set it up: (because it is was destroyed when the house of Israel was sifted).