Damp spots on internal walls

[Pez]

I've got a problem with a few isolated damp patches on internal walls in my house. Its a mid terrace, brick, built in the 30s. There is a damp course on the outside, but I'm not sure about the inside, and the floors are solid.
All the damp patches are on internal walls and on the chimney breast, between 30cm and 1.5m up from the floor.
I tried painting some of that blocking paint stuff on to hide them away, but they have gone all lumpy like the paint has bubbled off the wall.
I'm broke and am going to be selling my house soon hopefully, so am looking for a quick fix that isn't expensive! Any ideas?

[stoneyboy]

Pez,
Do what many seller try - hang pictures/mirrors over the offending areas.
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