Ahoy, ivan!
It appears the money was to be paid to American citizens, not to Spain:
ARTICLE 11
The United States, exonerating Spain from all demands in future, on account of the claims of their Citizens, to which the renunciations herein contained extend, and considering them entirely cancelled, undertake to make satisfaction for the same, to an amount not exceeding Five Millions of Dollars. To ascertain the full amount and validity of those claims, a Commission, to consist of three Commissioners, Citizens of the United States, shall be appointed by the President, by and with the advice and consent of the Senate; which Commission shall meet at the City of Washington, and within the space of three years, from the time of their first meeting, shall receive, examine and decide upon the amount and validity of all the claims included within the descriptions above mentioned. The said Commissioners shall take an oath or affirmation, to be entered on the record of their proceedings, for the faithful and diligent discharge of their duties; and in case of the death, sickness, or necessary absence of any such Commissioner, his place may be supplied by the appointment, as aforesaid, or by the President of the United States during the recess of the Senate, of another Commissioner in his stead. The said Commissioners shall be authorized to hear and examine on oath every question relative to the said claims, and to receive all suitable authentic testimony concerning the same. And the Spanish Government shall furnish all such documents and elucidations as may be in their possession, for the adjustment of the said claims, according to the principles of Justice, the Laws of Nations, and the stipulations of the Treaty between the two Parties of 27th October 1795; the said Documents to be specified, when demanded at the instance of the said Commissioners. The payment of such claims as may be admitted and adjusted by the said Commissioners, or the major part of them, to an amount not exceeding Five Millions of Dollars, shall be made by the United States, either immediately at their Treasury or by the creation of Stock bearing an interest of Six per Cent per annum, payable from the proceeds of Sales of public lands within the Territories hereby ceded to the United States, or in such other manner as the Congress of the United States may prescribe by Law. The records of the proceedings of the said Commissioners, together with the vouchers and documents produced before them, relative to the claims to be adjusted and decided upon by them, shall, after the close of their transactions, be deposited in the Department of State of the United States; and copies of them or any part of them, shall be furnished to the Spanish Government, if required, at the demand of the Spanish Minister in the United States.
http://www.tamu.edu/ccbn/dewitt/adamonis.htm
If your sources show something different, please be so kind as to share them.
I suggested the Captain of the vessel that wrecked would be courtmartialed because just about the most serious thing a captain can do is lose his ship. If, indeed, the loss was due to an Act of God, then the courtmartial would be the formal military investigation that could clear his record (although probably not his name; chances are he would windup on the beach anyway).
I am very confident that if anyone lost $5M in US government funds - in 1821 or 1921 or 2021 - there would be a complete and well documented investigation.
Good luck to all,
~The Old Bookaroo