How big is the Mame-cd ? bigger than the EGBrowser cd?
Make sure that the REAL ps1/ps2 cd disc is bigger than the cd-r, or it wont boot.
Even with the swapmagic cd disc the max size u can boot is 632mb (unless u use breaker pro as toc disc)
Then there is the question on how did u make the mame-cd-r, using cdgenps2 (good) or sony cd/dvd generator (better)
Maybe its a media problem, have u tried that brand of cd-r before on the ps2? (some brands may not work on your ps2)
PSP 1.52 (DG), DS 001, XBOX v1.6B+Cheapmod+120GBHD, SM33, 50004+HDA10+120GBHD, SM32, BP11, 3900X, XBOX v1.6+Softmod, P4_2.666, GBASP, GBA,Celeron_700, DC, PS1, P2_300, TI85, Saturn, GBC, GBP, Megadrive, P75, Amiga 500, MS, 486SX25, Amstrad CPC464, ZX81