This "anotación de afección fiscal" is routine. What it means is that if you acquire a property, you can be liable for underpayment of tax by the previous owner. Specifically it refers to Impuesto sobre Transmisiones Patrimoniales (ITP) and Impuesto sobre Sucesiones y Donaciones (ISD). Liabilities for these taxes on a property are paid by autoliquidación (self-assessment). Hacienda reserves the right to review the payments for a period of five years to ensure that all the tax due was properly paid. If it wasn't, they will seek to recover it, and if they can't get it from the person who should have paid it, they will collect it from the new owner, since such tax is a charge associated with the property. So it means that the new owner is liable for any such taxes due as a result of underpayment revealed by a review of payments made.

It's well explained here:
http://basededatos.indicator.es/compraventa_inmobiliaria/_qu...

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Note added at 1 hr (2014-08-29 13:03:26 GMT)
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This discussion also helps to clarify the meaning:
http://www.lainmobiliaria.org/foros/viewtopic.php?t=13313

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Note added at 6 hrs (2014-08-29 17:43:48 GMT)
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Perhaps it would help if I try to clarify my answer, in view of some of the recent comments. "Afección" means the state of being "afecto a" (subject to) some charge. In this case, the property is "afecto a la revisión de impuestos": subject to tax audit (or review, or whatever you want to call it), that is, a review conducted by the tax authorities of tax paid or unpaid in the past. This is an elliptical way of saying that it is subject to any tax liability that may emerge as a result of such an audit or review. My suggested translation is also elliptical; it means something like "apart from being subject to any liabilities that may arise as a result of tax audit". I think you could dispense with "being subject to", which is already implied by "cargas" (it is clear from the previous bit that these "afecciones" are a "carga"), and simply say "liabilities arising from".

If you use "charges" for "afecciones", either you'll have to think of a different word for "cargas" (for which it's the natural translation), or you'll have an awkward and confusing repetition. And I can't quite see how you would construct the rest of the sentence after "charges", though I expect there is a way of doing it.

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Note added at 21 hrs (2014-08-30 09:19:03 GMT)
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By the way, I can't help noticing that in the previous question on "afecciones fiscales", from 2008, the accepted answer from Tom Thumb was "outstanding tax exposures {charges or liabilities}", with the explanation: "If a nota simple land search/office copy entires [sic, for entries?], then preferably outstanding tax liabilities." And a nota simple is probably what this is.