Afraid your question isn't specific enough to elicit directly helpful responses. Did you flash a custom ROM and are now experiencing problems with your phone after this? If so, what kind of problems? There are far too many custom ROMs out there for a generic solution to apply and, needless to say, a good deal of personal research and caution needs to be exercised before one proceeds with a custom ROM installation.
Well yes, I did specify the ROM name. It is quite literally called Nameless ROM. The problems that I am experiencing are with the latest nightlies and this instability specifically affects the the dialler applications, sometimes it works but most times whenever I get a call on my phone I just get the pop up "Unfortunately the dialler app has stopped"
I have wiped cache and dalvik cache, reflashed the ROM and the Gapps to no avail.
Apologies. I was also being too general in my response. I checked a few Nameless fora on the web and it would appear such instabilities are not uncommon with nightly builds as is often the case with all custom ROMs still undergoing development. Your best option might be to flash a stable version or, if not out of your preference, revert to stock.