Look at a measure that doesn't mean much to say there's no problem. I'll quote from the report at
http://www.ssa.gov/OACT/TR/TR08/II_project.html#105057 .
"The year-by-year relationship between income and cost rates shown in figure II.D2 illustrates the expected pattern of cash flows for the OASDI program over the full 75-year period. Under the intermediate assumptions, the OASDI cost rate is projected to increase rapidly and first exceed the income rate in 2017, producing cash-flow deficits thereafter. Redemption of trust fund assets will allow continuation of full benefit payments on a timely basis until 2041, when the trust funds are projected to become exhausted. This redemption process will require a flow of cash from the General Fund of the Treasury. Pressures on the Federal Budget will thus emerge well before 2041. Even if a trust fund’s assets are exhausted, however, tax income will continue to flow into the fund. Present tax rates are projected to be sufficient to pay 78 percent of scheduled benefits after trust fund exhaustion in 2041 and 75 percent of scheduled benefits in 2082."
Key word: "cash-flow deficits." They'll have to redeem trust fund assets. Then, in 2041, the trust fund runs out--later than previous projections.
"The balance of the combined trust funds peaks at $2.7 trillion in 2017 (in present value) and then turns downward. This cumulative amount continues to be positive, indicating trust fund assets, or reserves, through 2040. However, after 2040 this cumulative amount becomes negative, indicating a net unfunded obligation. Through the end of 2082, the combined funds have a present-value unfunded obligation of $4.3 trillion. This unfunded obligation represents 1.6 percent of future taxable payroll and 0.6 percent of future GDP, through the end of the 75-year projection period."
In other words, from 2017 to 2040 (note that it'll probably be a few years after 2040) $2.7 trillion will come from general governmental funds. That's $113 billion a year on average, under current projections, that'll be added to what the Congress has to apportion. It won't be averaged though, so there will be "Pressures on the Federal Budget will thus emerge well before 2041." At that point they'll have to decide to cut benefits smoothly (until they reach 78% or so) or just wait until 2041 and have a sudden cut-off. Or decide to raise taxes to cover the difference--keeping in mind that when that happens, the ratio of people paying/people receiving will not be all that favorable; any increase can happen smoothly and incrementally--and if done early enough, be kept low--or it can happen right at the end.
Increasing FICA now won't make much of a difference unless the excess is put in non-governmental securities (which will do two things, probably both bad: it'll place the money at risk, since financial securities are almost always risky; it'll make the government a shareholder, and place pressure on the government to get involved in stockholder issues). The best thing would be to dispose of the general fund deficit and work to pay down the national debt, while not increasing taxes so much that it costs either prosperity or money. (One analysis rather nicely showed that the top 1-5% of wage earners from about 1970 to the present paid just about the same percentage of their income in federal taxes in any given year--something to note. Simplifying quite a bit, when tax rates are high, they seek out more shelters; when rates are lower, they seek out shelters less.)